I want to set up Valkey with Directus, but I am failing to do so.

Step 1.) Deployed the Directus + Postgres template. Added Valkey from the template. Everything is running after this step.
Step 2.) Now I am adding the following variables to Directus based on the Directus config docs (https://docs.directus.io/self-hosted/config-options.html#redis)

REDISENABLED="true" REDIS="${{Valkey.VALKEYURL}}"
REDISHOST="${{Valkey.VALKEYHOST}}"
REDISPORT="${{Valkey.VALKEYPORT}}"
REDISUSERNAME="${{Valkey.VALKEYUSER}}"
REDISPASSWORD="${{Valkey.VALKEYPASSWORD}}"
CACHEENABLED="true" CACHESTORE="redis"

When deploying I get the following error: at GetAddrInfoReqWrap.onlookup as oncomplete
[ioredis] Unhandled error event: Error: getaddrinfo ENOTFOUND valkey.railway.internal

all the variables exist in Valkey (they come with the template) and the railway privat url is listed as valkey.railway.interal as well, but somehow Directus can't communicate with it (I guess).

any clue? thx