Silicon Technix Hostings allows a maximum of 20 simultaneous MySQL connections per cPanel.
If you exceed this limit, you will receive a max_user_connections error.
Typically, either your site has too much traffic for the shared server, or your site may be under attack.
It is your responsibility to fix this by updating your web framework to the newest version, optimizing/indexing databases, or upgrading to a dedicated server.
You may email support@silicontechnix.com to get a proper diagnosis and specific advice.