diff --git a/x-pack/plugins/actions/server/lib/axios_utils.test.ts b/x-pack/plugins/actions/server/lib/axios_utils.test.ts
index 0cbc3cdde0046..43f16b4863e9a 100644
--- a/x-pack/plugins/actions/server/lib/axios_utils.test.ts
+++ b/x-pack/plugins/actions/server/lib/axios_utils.test.ts
@@ -5,7 +5,7 @@
  * 2.0.
  */
 
-import axios from 'axios';
+import axios, { AxiosInstance } from 'axios';
 import { Agent as HttpsAgent } from 'https';
 import HttpProxyAgent from 'http-proxy-agent';
 import { HttpsProxyAgent } from 'https-proxy-agent';
@@ -320,6 +320,25 @@ describe('request', () => {
     expect(axiosMock.mock.calls[0][1].timeout).toBe(360000);
     expect(axiosMock.mock.calls[1][1].timeout).toBe(360001);
   });
+
+  test('throw an error if you use  baseUrl in your axios instance', async () => {
+    await expect(async () => {
+      await request({
+        axios: {
+          ...axios,
+          defaults: {
+            ...axios.defaults,
+            baseURL: 'https://here-we-go.com',
+          },
+        } as unknown as AxiosInstance,
+        url: '/test',
+        logger,
+        configurationUtilities,
+      });
+    }).rejects.toThrowErrorMatchingInlineSnapshot(
+      `"Do not use \\"baseURL\\" in the creation of your axios instance because you will mostly break proxy"`
+    );
+  });
 });
 
 describe('patch', () => {
diff --git a/x-pack/plugins/actions/server/lib/axios_utils.ts b/x-pack/plugins/actions/server/lib/axios_utils.ts
index bed2e512761a0..b623f427be681 100644
--- a/x-pack/plugins/actions/server/lib/axios_utils.ts
+++ b/x-pack/plugins/actions/server/lib/axios_utils.ts
@@ -41,6 +41,11 @@ export const request = async <T = unknown>({
   timeout?: number;
   sslOverrides?: SSLSettings;
 } & AxiosRequestConfig): Promise<AxiosResponse> => {
+  if (!isEmpty(axios?.defaults?.baseURL ?? '')) {
+    throw new Error(
+      `Do not use "baseURL" in the creation of your axios instance because you will mostly break proxy`
+    );
+  }
   const { httpAgent, httpsAgent } = getCustomAgents(
     configurationUtilities,
     logger,
diff --git a/x-pack/plugins/stack_connectors/server/connector_types/slack_api/index.test.ts b/x-pack/plugins/stack_connectors/server/connector_types/slack_api/index.test.ts
index 62e7cf771d3cb..37f0209e6f393 100644
--- a/x-pack/plugins/stack_connectors/server/connector_types/slack_api/index.test.ts
+++ b/x-pack/plugins/stack_connectors/server/connector_types/slack_api/index.test.ts
@@ -32,6 +32,10 @@ const requestMock = utils.request as jest.Mock;
 
 const services: Services = actionsMock.createServices();
 const mockedLogger: jest.Mocked<Logger> = loggerMock.create();
+const headers = {
+  Authorization: 'Bearer some token',
+  'Content-type': 'application/json; charset=UTF-8',
+};
 
 let connectorType: SlackApiConnectorType;
 let configurationUtilities: jest.Mocked<ActionsConfigurationUtilities>;
@@ -266,9 +270,10 @@ describe('execute', () => {
     expect(requestMock).toHaveBeenCalledWith({
       axios,
       configurationUtilities,
+      headers,
       logger: mockedLogger,
       method: 'post',
-      url: 'chat.postMessage',
+      url: 'https://slack.com/api/chat.postMessage',
       data: { channel: 'general', text: 'some text' },
     });
 
@@ -317,9 +322,10 @@ describe('execute', () => {
     expect(requestMock).toHaveBeenCalledWith({
       axios,
       configurationUtilities,
+      headers,
       logger: mockedLogger,
       method: 'get',
-      url: 'conversations.info?channel=ZXCVBNM567',
+      url: 'https://slack.com/api/conversations.info?channel=ZXCVBNM567',
     });
 
     expect(response).toEqual({
diff --git a/x-pack/plugins/stack_connectors/server/connector_types/slack_api/service.test.ts b/x-pack/plugins/stack_connectors/server/connector_types/slack_api/service.test.ts
index 068bd8d5d923e..fa3e5d01b79d8 100644
--- a/x-pack/plugins/stack_connectors/server/connector_types/slack_api/service.test.ts
+++ b/x-pack/plugins/stack_connectors/server/connector_types/slack_api/service.test.ts
@@ -116,10 +116,14 @@ describe('Slack API service', () => {
       await service.validChannelId('channel_id_1');
       expect(requestMock).toHaveBeenCalledWith({
         axios,
+        headers: {
+          Authorization: 'Bearer token',
+          'Content-type': 'application/json; charset=UTF-8',
+        },
         logger,
         configurationUtilities,
         method: 'get',
-        url: 'conversations.info?channel=channel_id_1',
+        url: 'https://slack.com/api/conversations.info?channel=channel_id_1',
       });
     });
 
@@ -146,10 +150,14 @@ describe('Slack API service', () => {
       expect(requestMock).toHaveBeenCalledTimes(1);
       expect(requestMock).toHaveBeenNthCalledWith(1, {
         axios,
+        headers: {
+          Authorization: 'Bearer token',
+          'Content-type': 'application/json; charset=UTF-8',
+        },
         logger,
         configurationUtilities,
         method: 'post',
-        url: 'chat.postMessage',
+        url: 'https://slack.com/api/chat.postMessage',
         data: { channel: 'general', text: 'a message' },
       });
     });
@@ -166,10 +174,14 @@ describe('Slack API service', () => {
       expect(requestMock).toHaveBeenCalledTimes(1);
       expect(requestMock).toHaveBeenNthCalledWith(1, {
         axios,
+        headers: {
+          Authorization: 'Bearer token',
+          'Content-type': 'application/json; charset=UTF-8',
+        },
         logger,
         configurationUtilities,
         method: 'post',
-        url: 'chat.postMessage',
+        url: 'https://slack.com/api/chat.postMessage',
         data: { channel: 'QWEERTYU987', text: 'a message' },
       });
     });
@@ -183,9 +195,13 @@ describe('Slack API service', () => {
       expect(requestMock).toHaveBeenNthCalledWith(1, {
         axios,
         logger,
+        headers: {
+          Authorization: 'Bearer token',
+          'Content-type': 'application/json; charset=UTF-8',
+        },
         configurationUtilities,
         method: 'post',
-        url: 'chat.postMessage',
+        url: 'https://slack.com/api/chat.postMessage',
         data: { channel: 'QWEERTYU987', text: 'a message' },
       });
     });
diff --git a/x-pack/plugins/stack_connectors/server/connector_types/slack_api/service.ts b/x-pack/plugins/stack_connectors/server/connector_types/slack_api/service.ts
index f4ecb95571257..63746cc85dc78 100644
--- a/x-pack/plugins/stack_connectors/server/connector_types/slack_api/service.ts
+++ b/x-pack/plugins/stack_connectors/server/connector_types/slack_api/service.ts
@@ -120,13 +120,11 @@ export const createExternalService = (
     throw Error(`[Action][${SLACK_CONNECTOR_NAME}]: Wrong configuration.`);
   }
 
-  const axiosInstance = axios.create({
-    baseURL: SLACK_URL,
-    headers: {
-      Authorization: `Bearer ${token}`,
-      'Content-type': 'application/json; charset=UTF-8',
-    },
-  });
+  const axiosInstance = axios.create();
+  const headers = {
+    Authorization: `Bearer ${token}`,
+    'Content-type': 'application/json; charset=UTF-8',
+  };
 
   const validChannelId = async (
     channelId: string
@@ -138,7 +136,8 @@ export const createExternalService = (
           configurationUtilities,
           logger,
           method: 'get',
-          url: `conversations.info?channel=${channelId}`,
+          headers,
+          url: `${SLACK_URL}conversations.info?channel=${channelId}`,
         });
       };
       if (channelId.length === 0) {
@@ -198,9 +197,10 @@ export const createExternalService = (
       const result: AxiosResponse<PostMessageResponse> = await request({
         axios: axiosInstance,
         method: 'post',
-        url: 'chat.postMessage',
+        url: `${SLACK_URL}chat.postMessage`,
         logger,
         data: { channel: channelToUse, text },
+        headers,
         configurationUtilities,
       });
 
diff --git a/x-pack/plugins/stack_connectors/server/routes/valid_slack_api_channels.ts b/x-pack/plugins/stack_connectors/server/routes/valid_slack_api_channels.ts
index 434f989f56e92..cd2cb113a6750 100644
--- a/x-pack/plugins/stack_connectors/server/routes/valid_slack_api_channels.ts
+++ b/x-pack/plugins/stack_connectors/server/routes/valid_slack_api_channels.ts
@@ -48,13 +48,7 @@ export const validSlackApiChannelsRoute = (
   ): Promise<IKibanaResponse> {
     const { authToken, channelIds } = req.body;
 
-    const axiosInstance = axios.create({
-      baseURL: SLACK_URL,
-      headers: {
-        Authorization: `Bearer ${authToken}`,
-        'Content-type': 'application/json; charset=UTF-8',
-      },
-    });
+    const axiosInstance = axios.create();
 
     const validChannelId = (
       channelId: string = ''
@@ -62,9 +56,13 @@ export const validSlackApiChannelsRoute = (
       return request<ValidChannelResponse>({
         axios: axiosInstance,
         configurationUtilities,
+        headers: {
+          Authorization: `Bearer ${authToken}`,
+          'Content-type': 'application/json; charset=UTF-8',
+        },
         logger,
         method: 'get',
-        url: `conversations.info?channel=${channelId}`,
+        url: `${SLACK_URL}conversations.info?channel=${channelId}`,
       });
     };