Meeting Rooms booking is not working or getting a bounce back message when sending email from group mailbox?
You need to exclude these mailbox resources from Xink ReRouting rule.
Login to Office 365 admin or Exchange admin portal go to "mail flow" find Xink-Auto-ReRouting-Catcher and edit it as shown below.
Replicate the configuration (below image) and then add affected meeting rooms or shared mailboxes as "Except if" sender = type 'meeting room' and recipient = type 'meeting room' and then Lastly, click Save.
Note: You may also apply this solution if you are getting bounce-back messages or having a problem sending or receiving emails on a particular service account or mailbox. You can you also exclude those mailboxes from getting rerouted by Xink-Auto-ReRouting-Catcher