Need Help: osTicket + Microsoft 365 OAuth2 (Shared Mailboxes) Setup

himala

Hi everyone,

I’m currently setting up osTicket with Microsoft 365 using the OAuth2 (Microsoft Graph) integration and running into some challenges.

My environment:

Microsoft 365 tenant (Global Admin access)

support@ mailbox is licensed

Multiple shared mailboxes (noc@, billing@ — no licenses)

osTicket latest version with Microsoft OAuth2 plugin

What I need help with:

Proper Azure App Registration configuration (permissions, consent, scopes)

Connecting osTicket to Microsoft 365 via OAuth2

Ensuring osTicket can:

Fetch emails from support@ (licensed mailbox)

Fetch emails from shared mailboxes (noc@, billing@)

Send replies using the correct mailbox address for each department

Verifying correct permissions (Send As / Full Access) for shared mailboxes

Troubleshooting any issues with email fetching or routing

Important notes:

I prefer to do this via a guided screen-sharing session (for security reasons, I won’t be sharing credentials)

Happy to compensate for your time

If you’ve successfully implemented this exact setup with osTicket + Microsoft 365 OAuth2, please reply or message me.

Thanks in advance!

KevinTheJedi

himala

It can handle everything you described. All of this is explained in the links below; no need to waste your money:

The only difference is with shared mailboxes you have to add a licensed account that you can authenticate as (important) to the Send As and Read and Manage permissions for each shared mailbox. Then once you configure the OAuth2, the first tab in the Config popup make sure you uncheck (disable) Strict Matching. This is what allows the system to use a different user to auth than the actual address itself. Note it may throw an error the first time. If that happens just make sure it's unchecked and reauthorize.

Also, when you get directed to Microsoft to authenticate:

For the licensed email login as that user and authorize.
For the shared mailboxes make sure you login as the licensed user that has the appropriate permissions.

The rest is so easy, a caveman can do it.

Cheers.