Gmail new emails are not shown in Outlook for Mac

Our work email is on Google Workspace. I have been using Outlook for Mac to access the email account for over 1 year. Since Mar 30 suddenly Outlook stopped receiving new emails. I can still send emails out, but new emails are not synchronized any more. I tried to connect to Gmail with IMAP, all the latest emails are shown in Outlook. I reconnected the email account again with auto configuration by "Microsoft apps & services", emails are shown up to Mar 30, 2023 still. I tried on a different Macbook and got the same result, email received up to Mar 30. Changed to IMAP and then all latest emails are received.