@Dommicentl As I understand you are trying to delete Azure AD B2C tenant and getting the above mentioned error ( in the question), error states there are some enterprise applications are present in the tenant due to which you are unable to delete.
Try to delete the apps within the tenant, by following the below steps
- Browse to AAD Portal -> Enterprise Applications -> Change filter to All \ Any \ Any -> Delete the applications if you see in the list.
- Browse to Properties blade of each app -> Delete or if you can't delete them change "Enable for users to sign-in" to No
Also you can refer to this How do I delete my Azure AD B2C tenant? and let me know if the issue still persists, we can connect offline and troubleshoot further.
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