We are in a hybrid environment with M365 (AD sync only and have migrated from on-prem exchange 9 months ago). I am unable to modify a mail-enabled security group in M365. I receive the message in the Exchange Online Admin Center "You can only manage this group in your on-premises environment". We killed our on-prem Exchange Server several months ago after migrating. I also do not see an option to set this in our on-prem AD. How do I go about modifying this?
Thank you!

