Full error message is "1046 - Authentication Failure. The supplied user credentials failed validation for the requested service." (using Capium).
My agent credentials haven't changed and I can successfully log on to the HMRC and see all my clients. SA service is of course activated.
I can't get through to the Online Services Helpdesk.
Could this be related to another agent currently having authorisation? Normally authorisations have no impact on submissions.