Issue:
We have received Non Delivery Messages with ErrorCode=2
You can use Graph Explorer to verify the Domains configured within your Tenant.
You will need Admin Access to your Tenant to run this query.
Below are the steps.
1. Go to: Graph Explorer then sign in with your M365 Tenant
2. After logging in, copy and paste the below query (see below) > Click "Run query", please see below as an example of the output
See example below: GET https://graph.microsoft.com/v1.0/organization
3. As you scroll down you should be able to see a section called "verifiedDomains".
4. Check the configured Domain within your Tenant and make sure that in the "capabilities" list "Email" is present.
Follow the Microsoft instructions to validate this domain.
To ensure this new domain has been updated, edit a signature in Crossware (Microsoft will update the domains list for Crossware to use).