Error 508 is an alert warning you that your website has reached the available resources for the associated plan that is going to be temporary suspended, to avoid to comprise the whole server and all the other hosted websites. When you see the error you can go and check it in your cPanel by clicking the "Resource Usage" icon.
This event may occur in several occasions, such as:
- a peak of visits
- unoptimized CMS and related database
- a heavy script or cronjob gone loop
- a heavy backend operation (such as DB optimization, thumbnail reconstruction, etc.)
- a CMS or one of its component's bug.
We recommend to keep your CMS and its components updated and to check if there can be a timing connection between the alert message and one of the event described above.
In the end, you can consider to let an expert check the CMS or upgrade your current plan.