diff --git a/x-pack/plugins/actions/server/builtin_action_types/lib/axios_utils.test.ts b/x-pack/plugins/actions/server/builtin_action_types/lib/axios_utils.test.ts
index 844aa6d2de7ed..7e938e766657c 100644
--- a/x-pack/plugins/actions/server/builtin_action_types/lib/axios_utils.test.ts
+++ b/x-pack/plugins/actions/server/builtin_action_types/lib/axios_utils.test.ts
@@ -65,7 +65,7 @@ describe('request', () => {
       logger,
       proxySettings: {
         proxyUrl: 'http://localhost:1212',
-        rejectUnauthorizedCertificates: false,
+        proxyRejectUnauthorizedCertificates: false,
       },
     });
 
diff --git a/x-pack/plugins/actions/server/builtin_action_types/lib/get_proxy_agent.test.ts b/x-pack/plugins/actions/server/builtin_action_types/lib/get_proxy_agent.test.ts
index 2468fab8c6ac5..8623a67e8a68e 100644
--- a/x-pack/plugins/actions/server/builtin_action_types/lib/get_proxy_agent.test.ts
+++ b/x-pack/plugins/actions/server/builtin_action_types/lib/get_proxy_agent.test.ts
@@ -14,7 +14,7 @@ const logger = loggingSystemMock.create().get() as jest.Mocked<Logger>;
 describe('getProxyAgent', () => {
   test('return HttpsProxyAgent for https proxy url', () => {
     const agent = getProxyAgent(
-      { proxyUrl: 'https://someproxyhost', rejectUnauthorizedCertificates: false },
+      { proxyUrl: 'https://someproxyhost', proxyRejectUnauthorizedCertificates: false },
       logger
     );
     expect(agent instanceof HttpsProxyAgent).toBeTruthy();
@@ -22,7 +22,7 @@ describe('getProxyAgent', () => {
 
   test('return HttpProxyAgent for http proxy url', () => {
     const agent = getProxyAgent(
-      { proxyUrl: 'http://someproxyhost', rejectUnauthorizedCertificates: false },
+      { proxyUrl: 'http://someproxyhost', proxyRejectUnauthorizedCertificates: false },
       logger
     );
     expect(agent instanceof HttpProxyAgent).toBeTruthy();
diff --git a/x-pack/plugins/actions/server/builtin_action_types/lib/get_proxy_agent.ts b/x-pack/plugins/actions/server/builtin_action_types/lib/get_proxy_agent.ts
index bb4dadd3a4698..957d31546b019 100644
--- a/x-pack/plugins/actions/server/builtin_action_types/lib/get_proxy_agent.ts
+++ b/x-pack/plugins/actions/server/builtin_action_types/lib/get_proxy_agent.ts
@@ -23,7 +23,7 @@ export function getProxyAgent(
       protocol: proxyUrl.protocol,
       headers: proxySettings.proxyHeaders,
       // do not fail on invalid certs if value is false
-      rejectUnauthorized: proxySettings.rejectUnauthorizedCertificates,
+      rejectUnauthorized: proxySettings.proxyRejectUnauthorizedCertificates,
     });
   } else {
     return new HttpProxyAgent(proxySettings.proxyUrl);
diff --git a/x-pack/plugins/actions/server/builtin_action_types/lib/send_email.test.ts b/x-pack/plugins/actions/server/builtin_action_types/lib/send_email.test.ts
index f69a2fc1d209c..b6c4a4ea882e5 100644
--- a/x-pack/plugins/actions/server/builtin_action_types/lib/send_email.test.ts
+++ b/x-pack/plugins/actions/server/builtin_action_types/lib/send_email.test.ts
@@ -73,7 +73,7 @@ describe('send_email module', () => {
       },
       {
         proxyUrl: 'https://example.com',
-        rejectUnauthorizedCertificates: false,
+        proxyRejectUnauthorizedCertificates: false,
       }
     );
     // @ts-expect-error
@@ -140,6 +140,9 @@ describe('send_email module', () => {
           "host": "example.com",
           "port": 1025,
           "secure": false,
+          "tls": Object {
+            "rejectUnauthorized": undefined,
+          },
         },
       ]
     `);
diff --git a/x-pack/plugins/actions/server/builtin_action_types/lib/send_email.ts b/x-pack/plugins/actions/server/builtin_action_types/lib/send_email.ts
index a4f32f1880cb5..dead8fee63d4f 100644
--- a/x-pack/plugins/actions/server/builtin_action_types/lib/send_email.ts
+++ b/x-pack/plugins/actions/server/builtin_action_types/lib/send_email.ts
@@ -19,6 +19,7 @@ export interface SendEmailOptions {
   routing: Routing;
   content: Content;
   proxySettings?: ProxySettings;
+  rejectUnauthorized?: boolean;
 }
 
 // config validation ensures either service is set or host/port are set
@@ -45,7 +46,7 @@ export interface Content {
 
 // send an email
 export async function sendEmail(logger: Logger, options: SendEmailOptions): Promise<unknown> {
-  const { transport, routing, content, proxySettings } = options;
+  const { transport, routing, content, proxySettings, rejectUnauthorized } = options;
   const { service, host, port, secure, user, password } = transport;
   const { from, to, cc, bcc } = routing;
   const { subject, message } = content;
@@ -68,15 +69,18 @@ export async function sendEmail(logger: Logger, options: SendEmailOptions): Prom
     transportConfig.host = host;
     transportConfig.port = port;
     transportConfig.secure = !!secure;
-    if (proxySettings && !transportConfig.secure) {
+
+    if (proxySettings) {
       transportConfig.tls = {
         // do not fail on invalid certs if value is false
-        rejectUnauthorized: proxySettings?.rejectUnauthorizedCertificates,
+        rejectUnauthorized: proxySettings?.proxyRejectUnauthorizedCertificates,
       };
-    }
-    if (proxySettings) {
       transportConfig.proxy = proxySettings.proxyUrl;
       transportConfig.headers = proxySettings.proxyHeaders;
+    } else if (!transportConfig.secure) {
+      transportConfig.tls = {
+        rejectUnauthorized,
+      };
     }
   }
 
diff --git a/x-pack/plugins/actions/server/builtin_action_types/slack.test.ts b/x-pack/plugins/actions/server/builtin_action_types/slack.test.ts
index b15d92cecba62..d98a41ed1f355 100644
--- a/x-pack/plugins/actions/server/builtin_action_types/slack.test.ts
+++ b/x-pack/plugins/actions/server/builtin_action_types/slack.test.ts
@@ -167,7 +167,7 @@ describe('execute()', () => {
       params: { message: 'this invocation should succeed' },
       proxySettings: {
         proxyUrl: 'https://someproxyhost',
-        rejectUnauthorizedCertificates: false,
+        proxyRejectUnauthorizedCertificates: false,
       },
     });
     expect(response).toMatchInlineSnapshot(`
@@ -206,7 +206,7 @@ describe('execute()', () => {
       params: { message: 'this invocation should succeed' },
       proxySettings: {
         proxyUrl: 'https://someproxyhost',
-        rejectUnauthorizedCertificates: false,
+        proxyRejectUnauthorizedCertificates: false,
       },
     });
     expect(mockedLogger.debug).toHaveBeenCalledWith(
diff --git a/x-pack/plugins/actions/server/config.test.ts b/x-pack/plugins/actions/server/config.test.ts
index ac815a425a2b7..1d7edd5f6b38f 100644
--- a/x-pack/plugins/actions/server/config.test.ts
+++ b/x-pack/plugins/actions/server/config.test.ts
@@ -18,7 +18,8 @@ describe('config validation', () => {
           "*",
         ],
         "preconfigured": Object {},
-        "rejectUnauthorizedCertificates": true,
+        "proxyRejectUnauthorizedCertificates": true,
+        "rejectUnauthorized": true,
       }
     `);
   });
@@ -34,7 +35,8 @@ describe('config validation', () => {
           },
         },
       },
-      rejectUnauthorizedCertificates: false,
+      proxyRejectUnauthorizedCertificates: false,
+      rejectUnauthorized: false,
     };
     expect(configSchema.validate(config)).toMatchInlineSnapshot(`
       Object {
@@ -55,7 +57,8 @@ describe('config validation', () => {
             "secrets": Object {},
           },
         },
-        "rejectUnauthorizedCertificates": false,
+        "proxyRejectUnauthorizedCertificates": false,
+        "rejectUnauthorized": false,
       }
     `);
   });
diff --git a/x-pack/plugins/actions/server/config.ts b/x-pack/plugins/actions/server/config.ts
index 087a08f572c65..8823cea9f4452 100644
--- a/x-pack/plugins/actions/server/config.ts
+++ b/x-pack/plugins/actions/server/config.ts
@@ -34,7 +34,8 @@ export const configSchema = schema.object({
   }),
   proxyUrl: schema.maybe(schema.string()),
   proxyHeaders: schema.maybe(schema.recordOf(schema.string(), schema.string())),
-  rejectUnauthorizedCertificates: schema.boolean({ defaultValue: true }),
+  proxyRejectUnauthorizedCertificates: schema.boolean({ defaultValue: true }),
+  rejectUnauthorized: schema.boolean({ defaultValue: true }),
 });
 
 export type ActionsConfig = TypeOf<typeof configSchema>;
diff --git a/x-pack/plugins/actions/server/plugin.test.ts b/x-pack/plugins/actions/server/plugin.test.ts
index 4fdf9f2523568..9d545600e61ee 100644
--- a/x-pack/plugins/actions/server/plugin.test.ts
+++ b/x-pack/plugins/actions/server/plugin.test.ts
@@ -34,7 +34,8 @@ describe('Actions Plugin', () => {
         enabledActionTypes: ['*'],
         allowedHosts: ['*'],
         preconfigured: {},
-        rejectUnauthorizedCertificates: true,
+        proxyRejectUnauthorizedCertificates: true,
+        rejectUnauthorized: true,
       });
       plugin = new ActionsPlugin(context);
       coreSetup = coreMock.createSetup();
@@ -195,7 +196,8 @@ describe('Actions Plugin', () => {
             secrets: {},
           },
         },
-        rejectUnauthorizedCertificates: true,
+        proxyRejectUnauthorizedCertificates: true,
+        rejectUnauthorized: true,
       });
       plugin = new ActionsPlugin(context);
       coreSetup = coreMock.createSetup();
diff --git a/x-pack/plugins/actions/server/plugin.ts b/x-pack/plugins/actions/server/plugin.ts
index 413e6663105b8..a6c5899281658 100644
--- a/x-pack/plugins/actions/server/plugin.ts
+++ b/x-pack/plugins/actions/server/plugin.ts
@@ -323,7 +323,8 @@ export class ActionsPlugin implements Plugin<Promise<PluginSetupContract>, Plugi
           ? {
               proxyUrl: this.actionsConfig.proxyUrl,
               proxyHeaders: this.actionsConfig.proxyHeaders,
-              rejectUnauthorizedCertificates: this.actionsConfig.rejectUnauthorizedCertificates,
+              proxyRejectUnauthorizedCertificates: this.actionsConfig
+                .proxyRejectUnauthorizedCertificates,
             }
           : undefined,
     });
diff --git a/x-pack/plugins/actions/server/types.ts b/x-pack/plugins/actions/server/types.ts
index 0a7d6bf01b7ec..3e92ca331bb93 100644
--- a/x-pack/plugins/actions/server/types.ts
+++ b/x-pack/plugins/actions/server/types.ts
@@ -145,5 +145,5 @@ export interface ActionTaskExecutorParams {
 export interface ProxySettings {
   proxyUrl: string;
   proxyHeaders?: Record<string, string>;
-  rejectUnauthorizedCertificates: boolean;
+  proxyRejectUnauthorizedCertificates: boolean;
 }
diff --git a/x-pack/test/alerting_api_integration/common/config.ts b/x-pack/test/alerting_api_integration/common/config.ts
index 67dd8c877e378..f9fdfaed1c79b 100644
--- a/x-pack/test/alerting_api_integration/common/config.ts
+++ b/x-pack/test/alerting_api_integration/common/config.ts
@@ -63,7 +63,7 @@ export function createTestConfig(name: string, options: CreateTestConfigOptions)
     const actionsProxyUrl = options.enableActionsProxy
       ? [
           `--xpack.actions.proxyUrl=http://localhost:${proxyPort}`,
-          '--xpack.actions.rejectUnauthorizedCertificates=false',
+          '--xpack.actions.proxyRejectUnauthorizedCertificates=false',
         ]
       : [];