diff --git a/packages/insomnia/src/common/__tests__/constants.test.ts b/packages/insomnia/src/common/__tests__/constants.test.ts
index ad6d06211dd..46ae0868760 100644
--- a/packages/insomnia/src/common/__tests__/constants.test.ts
+++ b/packages/insomnia/src/common/__tests__/constants.test.ts
@@ -91,7 +91,7 @@ describe('getContentTypeName', () => {
 describe('getMockSeviceBinUrl', () => {
   it('should add subdomain when using insomnia cloud', () => {
     expect(getMockServiceBinURL('xyz', '/my-route', undefined)).toBe('https://xyz.mock.insomnia.rest/my-route');
-    expect(getMockServiceBinURL('mock_123', '/my-route', undefined)).toBe('https://mock_123.mock.insomnia.rest/my-route');
+    expect(getMockServiceBinURL('mock_123', '/my-route', undefined)).toBe('https://mock-123.mock.insomnia.rest/my-route');
     expect(getMockServiceBinURL('mock_123', '/my-route', 'http://localhost:8080')).toBe('http://localhost:8080/bin/mock_123/my-route');
   });
 });
diff --git a/packages/insomnia/src/common/constants.ts b/packages/insomnia/src/common/constants.ts
index 1735cee3566..573104ee121 100644
--- a/packages/insomnia/src/common/constants.ts
+++ b/packages/insomnia/src/common/constants.ts
@@ -122,7 +122,7 @@ export const getMockServiceBinURL = (serverId: string, path: string, customUrl?:
   if (serverId && !customUrl) {
     const baseUrl = getMockServiceURL();
     const url = new URL(baseUrl);
-    url.host = serverId + '.' + url.host;
+    url.host = serverId.replace('_', '-') + '.' + url.host;
     return url.origin + path;
   }
   return customUrl + '/bin/' + serverId + path;