Can't load PhotoStation on DSM6

[naasking]

I can't seem to load the browser-based photo station UI in DSM6. I get the error:

SQLSTATE[08006] [7] FATAL: Peer authentication failed for user "PhotoStation"

When I login using psql -U postgres and then execute \du, I see the right users/roles:

postgres=# \du
List of roles
Role name | Attributes | Member of
----------------------------+------------------------------------------------+--------------
AudioStation | | {MediaIndex}
DownloadStation | | {}
MailStation | | {}
MediaIndex | | {}
PhotoStation | | {}
SynologyApplicationService | Create DB | {}
SynologyMoments | Create DB | {}
postgres | Superuser, Create role, Create DB, Replication | {}

Everything else works, ie. mail station, download station, Moments, etc. it's just PhotoStation that does not. The same problem occurs with both PHP7.0 and PHP5.6.

Postgres' peer authentication queries the system for the system user corresponding to the provided login, and /etc/passwd does contain PhotoStation as a user and a group, with the same configuration as the other service users that all work, so I'm not sure where the exact failure is. The postgres log file, /var/log/postgresql.log, shows the following lines:

2021-01-03T12:29:23-05:00 MyServer postgres[1655]: [4-1] LOG: provided user name (PhotoStation) and authenticated user name (http) do not match
2021-01-03T12:29:23-05:00 MyServer postgres[1655]: [5-1] FATAL: Peer authentication failed for user "PhotoStation"
2021-01-03T12:29:23-05:00 MyServer postgres[1655]: [5-2] DETAIL: Connection matched pg_hba.conf line 3: "local all all peer"

I take from this that it's attempting to login as PhotoStation, but it's a web service running under the http user so that's the user that the system returns for peer authentication, and so it fails to match. Not sure how to resolve this, any thoughts?