Outlook and Google Suite (Gmail issues)

I am having an issue with a client utilizing Google (GSuite Paid) IMAP into Outlook...

Client is claiming that all emails are NOT syncing with Outlook. Client claims that they "logged into Gmail and tons of emails are not transferring". It appears that some emails are transferring, but not all. Any idea as to why this is? We have two other machines/users using the same setup that are not experiencing the same issues.

Please let me know if you have any support on this.

Thanks