Your hosting account was found to be causing an overload of MySQL resources. What can you do? Upgrade your Drupal 8 website to Drupal 8.4 or higher.
One of my goals in rebranding my website from CMS Report to socPub was to write diverse articles beyond the topic of content management systems. Yet, here we go again with another CMS related article. The Drupal open source project recently made available Drupal 8.4 and for me this version has been a long time coming as it addresses some long standing frustrations I've had with Drupal 8 from the perspective of a site administrator. While Drupal 8.4 adds some nice new features, I'm just as excited about the bug fixes and performance improvements delivered in this new version of Drupal.
When Drupal 8 was introduced it made significant improvements in how it caches and renders pages. That's great news for websites that use Drupal's built-in caching to speed up delivery of pages or page elements. But there was one unwanted side effect to the cache enhancements, excessive growth of cache tables with tens or hundreds of thousands of entries, and gigabytes in size. For my own website it is not too uncommon to see my database reach 4 GB in size. Let's put it this way, it was no fun to receive a letter from my hosting provider that they weren't too happy of my resource usage. Worse they threatened shutting down my website if I didn't manage the database size better. Just in the nick of time for you and me, Drupal 8.4 delivers a fix to the cache growth by introducing a new default limit of 5000 rows per cache bin.