Some browsers default configurations can block login on Bkper with your Google Account. If you can't login, you can try some of the steps bellow.
Unblock third party cookies
1) Go to your chrome cookies settings at this url: chrome://settings/content/cookies
2) Check "Allow all cookies"
Logged in to different Google Accounts at the same time?
Error 400: admin_policy_enforced?
Find Bkper and revoke access:
3. Go to https://app.bkper.com/ and login again
After authorization works, if you user any Add-on such Sheets or Forms, or Google Integration, you might need to reopen them and reauthorize too.