If you're trying to install SyncWith's Google Sheets addon from the Google Workspace Marketplace and you receive an error Bad request 400 error, this is an error from Google Workspace Marketplace (GWM), not SyncWith.
The error seems to happen when you have multiple google accounts logged into your browser at once, and the recommended solution is to logout all of your google accounts from your browser except one. Please see our article about what to do when you have multiple google accounts logged into your browser for more details and possible solutions.
You can read about users of other addons also facing this issue with GWM:
