Deprecated pgp keyserver
The standard configuration still has pool.sks-keyservers.net
set as keyserver: https://0xacab.org/schleuder/schleuder/-/blob/main/etc/schleuder.yml#L34
However, the keyserver is deprecated due to GDPR (source).
Maybe this could be changed to https://keys.openpgp.org/ or another new type of keyserver.