GA4 Error：Failed to register users

Issue

When adding a new user to GA4, I get the error: “Failed to register users,” as shown in the image:

Reason

A single Google account can access up to 100 GA4 accounts. If your Google account has reached this limit, adding a new user may fail with the error: “Failed to register users.”

Solution

Check the number of GA4 accounts in your Google account, remove some, and then reauthorize.