Artifact Signing: all sign operations return Failed/null after subscription was disabled and reactivated

Pay-As-You-Go subscription was Disabled (unpaid invoice) then reactivated. Artifact Signing account/profile looks healthy (Active, identity Completed) but every sign fails:

HTTP 200/202 then {"status":"Failed","signature":null,"errorResponse":null}

Same result from SignTool and from a direct REST digest sign (no local tooling). Cert rotation stopped during the disable window and resumed after reactivation; SignCompleted stays at zero.

Could someone from the Artifact Signing team check whether this account is stuck after the reactivation?

Example operation ID: 6286cf36-df9c-4a4d-8126-7d8344c34ff3