Step 1
Option A — Sign out of all accounts and sign back in: Go to https://accounts.google.com/ Click your account icon in the top right Select "Sign out of all accounts" at the bottom Sign back in with only the account you need for our extension. Try the extension again.
OR
Option B — Create a separate Chrome profile: Click the profile icon in Chrome Select "Add" to create a new Chrome profile Sign in with only the Google account you need for our extension Use our extension in this new profile
Step 2
Then create a new Google Slides Document and Try again. If none of these solutions work, please let me know, and I'll be happy to assist you further.
Please note -
This is an issue from Google's end. Here is the official guidance from Google on how to resolve this issue caused by multiple logins at the same time.