SIP Trunk Registration Fails with 401 Unauthorized During Zendesk Talk Migration

Configuration is broken for some reason… 401 Unauthorized errors are blocking SIP trunk registration. We are migrating from Zendesk Talk to Genesys Cloud and trying to replicate the simple PSTN setup, but the credentials accepted in Zendesk are rejected by the Genesys Cloud SIP trunk configuration. The environment is EU-West-1.