Using the New Outlook for Mac features in business environments
Dear Confused_man,
Thank you for using Microsoft products and posting in the Microsoft Support Community.
I realise that you want to create incoming mail rules for Gmail addresses in the Outlook application, but the error that appears under the Rules tab in the new Outlook settings is ‘Rules are not supported for this account’. There are no rules issues with your school account. Please let me know if I've misunderstood.
School accounts are able to add rules in Outlook, but Gmail personal accounts are not supported because rules are based on the account's local data files for rules related processing of emails, whereas new Outlook is a web-based application, and gmail personal accounts are configured with IMAP protocol in Outlook, which is not able to set rules in Outlook to set up rules. Similarly, even if you set up rules in gmail's mailbox, it will not be synchronised to Outlook because gmail's rules are based on the gmail server to execute.
Also, I need to correct you that the Gmail account added in Outlook app does not support Microsoft Exchange, this may be Microsoft sync technology interfering with you, it is actually a sync technology i.e. Outlook will sync gmail emails and not rules. You have enabled IMAP and POP in your Gmail account settings, by doing so it means that you have authorised IMAP and POP for gmail to allow configuration of the gmail account in Outlook, but the gmail personal account is a third party mailbox in Outlook, which does not apply to the Exchange protocol and does not have an automatic sync (create) rules feature.
I understand what you are saying that managing emails is an important task in your daily routine, so the remedy I can think of is that you can create rules in gmail for the purpose of managing emails. Whereas in Outlook you can only synchronise your gmail emails.
Although your expectations were not met due to objective facts, I hope I have explained the issue clearly to you and given you some remedies, and I thank you for your patience and support. Please feel free to let me know how it is going by answering below. I'd be happy to help you further.
Best Regards
Vivian.Y - MSFT | Microsoft Community Support Specialist