I was creating the same template for this then found yours

> The Docmost container connects to the Redis instance through the public URL. Connecting through the private URL results in errors. I am working on a fix.

I ran into this as well :( Part of me is wondering if it's because the private url takes a few seconds to initialize. The code seems to be accounting for this, but I'm not super familiar with nest.js.

https://github.com/docmost/docmost/blob/main/apps/server/src/integrations/health/redis.health.ts

Did you come across any other potential reasons? Would be good to avoid network egress charges.

Also you should add RAILWAY_RUN_UID=0 as a variable. Otherwise you can't upload images

https://docs.railway.app/guides/volumes#permissions

Thanks for the suggestion! I've added RAILWAY_RUN_UID=0 as a variable

As for the issues with the Redis connection being through the public URL, it's an upstream issue. Here's hoping they fix it:
https://github.com/docmost/docmost/issues/534

Docmost has finally pushed the fix that will allow connecting to REDIS via IPv6

I've updated the template to utilize the REDIS internal URL instead

I really appreciate the commitment and dedication, thank you!