[Mailman] Cron <mailman at lists> /usr/lib/mailman/cron/nightly_gzip

[Cron Daemon]

Traceback (most recent call last):
  File "/usr/lib/mailman/cron/nightly_gzip", line 154, in <module>
    main()
  File "/usr/lib/mailman/cron/nightly_gzip", line 140, in main
    compress(f)
  File "/usr/lib/mailman/cron/nightly_gzip", line 81, in compress
    outfp = gzip.open(txtfile+'.gz', 'wb', 6)
  File "/usr/lib64/python2.6/gzip.py", line 33, in open
    return GzipFile(filename, mode, compresslevel)
  File "/usr/lib64/python2.6/gzip.py", line 79, in __init__
    fileobj = self.myfileobj = __builtin__.open(filename, mode or 'rb')
IOError: [Errno 13] Permission denied: '/var/lib/mailman/archives/private/lago-devel/20160711.txt.gz'