Issue

When accessing (or logging into) a Mendix application, the default error pops up. In the console logs, the following error message can be seen:

 TypeError: Cannot read properties of null (reading 'insertBefore')

Environment

Studio Pro 9.24.3 and older

Cause

This error is caused by a conflict between the Mendix Client and the browser extension. Multiple browser extensions are known to cause the conflict. Some known extensions causing it are LastPass and React DevTools. 

Solution/Workaround

To resolve the error, the project must be upgraded to Mendix Studio Pro 9.24.4 (or newer) or Studio Pro 10.0.0 (or newer).

Alternatively, the Chrome extension(s) that cause the error can be disabled.  

Additional information

Not Applicable