Hello Teams Community,
Please i need your help on this issue.
An invitation has been sent to the client by an external organization but the user cannot accept the invitation because of this error: ADDB2B_0013 : your organization does not allow collaboration on the domain of the user you invited. Please contact your administrator to allow cooperation with this domain.
Organization is allowed teams to collaborate with other organizations. There are no collaboration restrictions in Azure Active Directory either.
Can you help us with the problem?