After changing the frontend, it issues a welcome page

I was install mastodon-fe and at now i take this error.
When i use

 mix pleroma.frontend install pleroma-fe --ref stable

10:31:41.667 [error] Postgrex.Protocol (#PID<0.506.0>) failed to connect: ** (Postgrex.Error) FATAL 28P01 (invalid_password) password authentication failed for user “postgres”

10:31:41.869 [error] Postgrex.Protocol (#PID<0.500.0>) failed to connect: ** (Postgrex.Error) FATAL 28P01 (invalid_password) password authentication failed for user “postgres”

10:31:44.496 [error] Postgrex.Protocol (#PID<0.503.0>) failed to connect: ** (Postgrex.Error) FATAL 28P01 (invalid_password) password authentication failed for user “postgres”

But at the config - user and database have name akkoma.
WTF?!

the postgres errors sound like you did not set MIX_ENV before running your mix commands as noted by the docs

additionally, you cannot set the mastodon frontend as your primary frontend, so that is likely why you’re seeing a welcome page