Same issue. Clicking Diagnose reported:

Update the deploy region in the service settings from "us-east4-eqdc4a" to a valid region like "iad". The deployment was rejected before building because the configured multi-region key "us-east4-eqdc4a" is not recognized as a valid region. The same commit deployed successfully earlier, confirming the region config is the only cause.

My third try did finally go through.

Hi folks, this is related to an incident we have ongoing which we're working towards fixing: https://status.railway.com/incident/US8W0QLQ

This is fully resolved now and the deploy queue has cleared. A fresh redeploy should go through normally. Closing this out.