I have tested using a trial O365 Business Standard license and it worked fine.

Hi Sufyan

Everything sounds correct, whilst you mention you have done what is in the instructions. Could I ask you to show the steps you have taken. Just in case something was missed or misunderstood. 

Hi Matthew,

ive followed these steps:
https://help.sagecrm.com/on_premise/en/2022R2/Administration/Content/Administrator/OT_OAuth2.0ExchangeOffice365.htm

ive set a few sites up all which have had no issues (apart from one where i deleted the app and re-created which then worked)

ive spoken with support who suggested to delete the import email app and also the exchange app and then re-create the exchange app but still getting the same error:

ERROR: checkExchangeUserEmail
CODE: 0
URL : /.../checkExchangeWebSiteAvailability
MSG : <CheckExchangeResponse><errorMessage>com.sage.scrm.syncengine.exchange.ews.service.error.SageExchangeServiceException: Parsed Exchange Exception:
Main exception string: An internal server error occurred. The operation failed., Mailbox 'a38d73e5-0eea-4734-aacb-439a5f3ee09f' doesn't have a valid license.

Exception code: ErrorInternalServerError
Detailed messages:
Message name: InnerErrorMessageText, message value=The license is invalid for this mailbox.
Message name: InnerErrorResponseCode, message value=ErrorInvalidLicense
Message name: InnerErrorDescriptiveLinkKey, message value=0</errorMessage><httpStatus>500</httpStatus></CheckExchangeResponse>

Just the one line of 'Doesn't have a valid licence' screams out at me, can you sign into the email account that you're using at mail.office365.com? 

yep can log into mail and into the admin centres (the crm@ account is a global admin)

It doesn't need to be a global admin account, just one with Application Impersonation role assigned to it. But in either case

Might be you will need to raise it with Sage support, I've never known the licence type to get in the way as most of ours are set up with the most basic one. 

ive logged with Sage support waiting for a reply back. Did some extra troubleshooting by connecting to exchange via powershell to see what this was referring to (Mailbox 'a38d73e5-0eea-4734-aacb-439a5f3ee09f' doesnt have a valid license) and doing the following query Get-EXOMailbox -Identity 'a38d73e5-0eea-4734-aacb-439a5f3ee09f'  returned a different mailbox to the one i am logging in with when setting up the exchange connection in CRM and this account doesnt have a mailbox - very strange

Thanks for the tip.  I am going to share this will colleagues in support.  It is frustrating that this was more or less "unplug it and then plug it in again".

im getting this same error on a different site, tried everything but it keep erroring saying mailbox doesnt have a valid license - has anyone seen this?