Can't list snaposhots on remote kopia client

When trying a kopia snap ls on a remote kopia client, which is connected to a Kopia server, I am getting this error after 182s of waiting:

ERROR error listing all snapshot manifests: unable to find snapshot manifests: unable to complete invoking GRPC API despite 10 retries: should retry

When running the same command on the kopia server itself, Kopia shows all the snapshots und the whole action runs for 136s. Now, this is a rather large repo with 100k+ snapshots, but since it runs locally, I’d expect it to also work remotely, which it definitively did 3 months ago.

Anybody else encountered this?