Server says client is connected, but no server is listed in "servers" array and cannot start back up

I have many containerized clients connecting to a containerized server, both locally and over the internet. The server container is hosted within a Linux VM bridged from a Linux Host. The working local clients are on a separate VM bridged from the same host machine. I also have internet clients which work just fine.

The clients which don’t work are in containers on VM’s bridged from a second local server on the same network. The server says that the client is online, but only updates their “last seen” variable once. (It continues to say “yes” for ‘online’ though)

The client says it is internet-connected but does not list any servers.

Trying to start a backup from the server results in an immediate “Starting backup failed”, with no other error information. I have temporarily disabled all firewalls on all involved local machines. I have tried connecting to the server both through a web hostname as well as its local IP.

This is client version 2.4.11.0 and server version 2.4.13.

No unusual logs are generated after the client initially starts. Calling service urbackupclientbackend restart results in the following errors:

2022-01-08 08:35:04: urbackupserver: No available slots… starting new Worker
2022-01-08 08:35:04: ClientService cmd: STATUS DETAIL#pw=pRFeB5bs2aolVvu3TOVXmVmRN1iWT3
2022-01-08 08:35:04: rc=0 hasError=true state=0
2022-01-08 08:35:06: ClientService cmd: STATUS DETAIL#pw=pRFeB5bs2aolVvu3TOVXmVmRN1iWT3
2022-01-08 08:35:06: rc=0 hasError=true state=0
2022-01-08 08:35:07: ClientService cmd: STATUS DETAIL#pw=pRFeB5bs2aolVvu3TOVXmVmRN1iWT3
2022-01-08 08:35:07: rc=0 hasError=true state=0
2022-01-08 08:35:08: ClientService cmd: STATUS DETAIL#pw=pRFeB5bs2aolVvu3TOVXmVmRN1iWT3
2022-01-08 08:35:08: rc=0 hasError=true state=0
2022-01-08 08:35:31: Trying to connect to internet server “backups.mydomain.net” at port 55415
2022-01-08 08:35:32: Successfully connected.
2022-01-08 08:35:50: ClientService cmd: STATUS DETAIL#pw=pRFeB5bs2aolVvu3TOVXmVmRN1iWT3
2022-01-08 08:35:50: rc=0 hasError=true state=0
2022-01-08 08:35:51: ClientService cmd: STATUS DETAIL#pw=pRFeB5bs2aolVvu3TOVXmVmRN1iWT3
2022-01-08 08:35:51: rc=0 hasError=true state=0
2022-01-08 08:35:52: ClientService cmd: STATUS DETAIL#pw=pRFeB5bs2aolVvu3TOVXmVmRN1iWT3
2022-01-08 08:35:52: rc=0 hasError=true state=0

Can someone explain what these errors mean and if they are related?

Figured out the issue again. The root /backup folder had the wrong file permissions. I set them to be urbackup:urbackup and now it works.