3178526 - Why can't I access a sourcing event with the username provided by my customer?

The buyer indicated me that they created an account for me and they sent me an email that contains an User ID for participating in a sourcing event. When I attempt to sign in, I receive an error that says: The username and password pair you entered was not found.

Create Account, Access Event, New User, Existing Account, Sourcing Event, Username , KBA , migration source: knowledge@ariba , registration by invitation (event partic , migrated on: 2022-04-02 16:34:38 , BNS-ARI-SS-EVT-LGN , Sourcing Event Registration/Login , BNS-ARI-SS , Strategic Sourcing , BNS-ARI-SLP-REG-LOG , Supplier Login Issues , BNS-ARI-SLP , Supplier Lifecycle & Performance , Problem