We're currently experiencing degraded performance in EU West, which is likely causing the issues you're seeing. Our team is actively investigating and working on a resolution. You can track the status here: https://status.railway.com/incident/cmmyzauck00u0otw5n72hhwax

Circling back, apologies it sat. A sudden inability to reach MongoDB with no code change is usually the host being rebooted, fixed by a redeploy onto a healthy host. Data is safe on the volume. Likely past it now; if not, reply and I'll look. — Angelo