borg backup error: “Failed to create/acquire the lock”

Using borg to backup is convenient and nice.

I installed it on my debian 10, ran it manually via a script multiple times without errors. Once I ran it via cron I got one of the following errors

Failed to create/acquire the lock <BackupDir>/lock (timeout).

and

Exception ignored in: <function Repository.__del__ at 0x7fb0a5c83d90> Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/borg/repository.py", line 179, in __del__
    assert False, "cleanup happened in Repository.__del__"
AssertionError: cleanup happened in Repository.__del__ Local Exception Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/borg/archiver.py", line 4455, in main
    exit_code = archiver.run(args)
  File "/usr/lib/python3/dist-packages/borg/archiver.py", line 4387, in run
    return set_ec(func(args))
  File "/usr/lib/python3/dist-packages/borg/archiver.py", line 139, in wrapper
    with repository:
  File "/usr/lib/python3/dist-packages/borg/repository.py", line 189, in __enter__
    self.open(self.path, bool(self.exclusive), lock_wait=self.lock_wait, lock=self.do_lock)
  File "/usr/lib/python3/dist-packages/borg/repository.py", line 396, in open
    with open(os.path.join(self.path, 'config')) as fd:
PermissionError: [Errno 13] Permission denied: '<BackupDir>/config'

I couldnt even run the script manually afterwards. I found the file <BackupDir>/lock.roster
,removed it and from here on no more problems: neither manually nor via cron.