If the command Convert-MsolDomainToFederated gives and error "Service not available" this can be caused by a existing federation to Office 365 is configured but without the "-SupportMultipleDomain" switch. Convert-MsolDomainToFederated gives and error "Service not available" The "-SupportMultipleDomain" switch will add a third Claim Rule to the federatation and the Convert-MsolDomainToFederated…