Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Hello ronchek thi,
Good day! Thank you for posting to the Microsoft Community.
From your provided information it seems that Room Mailbox calendar processing is set to AutoAccept but all the new meetings are tentative, in this scenario you must ensure there are no custom calendar processing settings applied to the mailbox that could be causing the issue (must be checked using PowerShell). I would also like to suggest posting your concern in the related community: PowerShell - Microsoft Q&A, to receive detailed help from the experts.
Apologies for redirecting you to a different community. The members in that category specialize in addressing unique concerns related to PowerShell and possess exceptional knowledge of this.
Redirecting you to the correct path will ensure faster and better assistance.
I appreciate your patience and understanding. Have a great day!
Sincerely,
Md Ashabul Haque | Microsoft Community Moderator