Mattermost notifications.log permission denied

Summary

/var/log/gitlab/mattermost/current shows

2022-02-15_19:50:22.36389 can't open new logfile: open notifications.log: permission denied
2022-02-15_19:50:22.36394 can't open new logfile: open notifications.log: permission denied

Steps to reproduce

Install Mattermost

What is the current bug behavior?

open notifications.log: permission denied error in /var/log/gitlab/mattermost/current

What is the expected correct behavior?

No error

GitLab version

16.0

Not new per #5177 (closed)