Fatal Error when accessing Civi in WP Install

Question

My Civi seems to be broken, and I'm really unsure why! This is the error I receive when trying to open the base CiviCRM homepage.

Fatal error: Uncaught CRM_Core_Exception: [0: Invalid cache key: Not a string thrown in /home2/snachodo/public_html/boyscoutstech/wp-content/plugins/civicrm/civicrm/CRM/Utils/Cache.php on line 221

Can anyone point to a resource to resolve the error?

A further complication that I didn't realize until this week is that I am unable to create new blog posts or pages in WordPress. I receive the same error as above. However, WordPress works when I deactivate CiviCRM as a plugin.

Log message below:

[22-Dec-2018 00:25:12 UTC] PHP Fatal error:  Interface 'Psr\SimpleCache\CacheInterface' not found in /home2/snachodo/public_html/boyscoutstech/wp-content/plugins/civicrm/civicrm/CRM/Utils/Cache/Interface.php on line 40
[22-Dec-2018 00:47:24 UTC] PHP Fatal error:  Interface 'Psr\SimpleCache\CacheInterface' not found in /home2/snachodo/public_html/boyscoutstech/wp-content/plugins/civicrm/civicrm/CRM/Utils/Cache/Interface.php on line 40
[22-Dec-2018 22:29:32 America/Denver] PHP Warning:  Declaration of CRM_Mailchimp_Permission::check($permissions) should be compatible with CRM_Core_Permission::check($permissions, $contactId = NULL) in /home2/snachodo/public_html/boyscoutstech/wp-content/uploads/civicrm/ext/uk.co.vedaconsulting.mailchimp/CRM/Mailchimp/Permission.php on line 40
[22-Dec-2018 22:29:38 America/Denver] PHP Warning:  Declaration of CRM_Mailchimp_Permission::check($permissions) should be compatible with CRM_Core_Permission::check($permissions, $contactId = NULL) in /home2/snachodo/public_html/boyscoutstech/wp-content/uploads/civicrm/ext/uk.co.vedaconsulting.mailchimp/CRM/Mailchimp/Permission.php on line 40
[22-Dec-2018 23:15:00 America/Denver] PHP Warning:  Declaration of CRM_Mailchimp_Permission::check($permissions) should be compatible with CRM_Core_Permission::check($permissions, $contactId = NULL) in /home2/snachodo/public_html/boyscoutstech/wp-content/uploads/civicrm/ext/uk.co.vedaconsulting.mailchimp/CRM/Mailchimp/Permission.php on line 40
[03-Jan-2019 09:02:18 America/Denver] PHP Warning:  Declaration of CRM_Mailchimp_Permission::check($permissions) should be compatible with CRM_Core_Permission::check($permissions, $contactId = NULL) in /home2/snachodo/public_html/boyscoutstech/wp-content/uploads/civicrm/ext/uk.co.vedaconsulting.mailchimp/CRM/Mailchimp/Permission.php on line 40

Answer 1

Unfortunately, the log message suggests you've hit a limit of your hosting provider.

User snachodo_657 already has more than 'max_user_connections'

This could have various causes. If your hosting plan only allows a certain number of DB connections simultaneously and your site creates more than that, you'd see this.

I don't think it's a common issue for CiviCRM so it may be that the hosting provider has a low number of permitted DB connections, OR that your site is busier than most sites on your hosting provider.

It's worth noting that CiviCRM's DB connection methodology does not re-use Wordpress's DB connection, so for any visitor on a CiviCRM page, your site will consume two DB connections at once.

In the first case, I'd contact your hosting provider and enquire about the limit. It might be a config tweak they can make, or they may offer you a plan with more DB connections.

If that doesn't work out, you could ask an expert to investigate why your site is making too many connections, or look into hosting providers who provide support for CiviCRM sites.

Hope that's some help!