Website is repeatedly deactivated

I have a strange problem with just one WordPress website. About once a day, though not at a regular time, the site becomes unavailable and users see the worrying message 'Your connection is not private: Attackers might be trying to steal your information' or similar. There appears to be problem with the site's certificate, but in fact on investigation it turns out that the site is deactivated in the ISPConfig control panel. When I re-activate it, the site returns to normal ... until the next time this happens. The certificate is fine.

Only I have admin access to the control panel, and I have disabled the client's access to it. Has anyone any idea what might be going on? For example, can the control panel itself deactivate a website under certain circumstances? I cannot find anything relevant in the site's debug.log or in the ISPConfig system log.

I'd appreciate any help with this.

System
Ubuntu 18.04.2 server (64-bit), fully up to date, with Apache 2.4.29, PHP7.2 and MySQL 15.1 (MariaDB)
ISPConfig 3.1.13p1
Website: www.cofe-equal-marriage.org.uk - WordPress 5.1.1

 

Does this user have traffic quota set? Is any other quota exceeded?
I tried to find in the Manual what happens when quota is exceeded, but did not find. But Internet Search Engines helped to find a discussion, that seems to say site gets disabled if traffic quota is exceeded.
https://www.howtoforge.com/community/threads/traffic-quota-exceeded.54257/#post-296379

 

Thank you, that's an interesting suggestion that I hadn't thought of. According to https://git.ispconfig.org/ispconfig/ispconfig3/issues/3937, "At the moment any webspace exceeding its traffic quota is sent an email via the nightly cronjob (00:30) and disabled afterwards". It's strange that this doesn't seem to be in the manual (unless you and I have both missed it).

I'll try increasing the traffic quota of the client and the website and see if that solves the problem.

 

That was it! Thank you.