When you complete the Microsoft® 365™ installation wizard in RM Unify, the compatibility check may fail with the following error:

'Nominated domain has no sub-domains in Microsoft 365'

This error message explains that the check to ensure the chosen domain has no sub-domains has failed, i.e. the domain does have sub-domains and so the federation is blocked.

This check will fail if it finds sub-domains (also known as child domains) registered in the Office tenancy using the domain you want to federate with RM Unify. It is not possible to federate a domain with existing sub-domains into RM Unify.

For example, if you want to federate the domain school.sch.uk, the compatibility check will fail if the domain primary.school.sch.uk is listed in the Domains settings in Microsoft 365. This is because primary.school.sch.uk is a sub-domain of school.sch.uk. 

 There are two options:

1. Remove the sub-domain from the Microsoft 365 tenancy.
2. Log a call with RM Support to request that Microsoft 'breaks' sub-domain inheritance.

Note: Once the sub-domain has been deleted, it will not be accessible to users. Before deletion, please ensure that any information on the sub-domain that you want to retain has also been made available elsewhere and users have been made aware of this change.

1. Log on to Microsoft 365 as an administrator user.
2. Browse to the Domains page in Microsoft 365.
3. In the Domains page, select the necessary domain name and click Remove.
4. In the 'Remove domain' page, click Yes.

If it is not possible to remove the sub-domain from the tenancy, please log a call with RM Support for further advice on how to proceed federating your desired domain.