Error establishing a database connection

Hi,

I have this website i’m building in which i get this ‘Error establishing a database connection’ error sometimes when ?clicking on the wishlist button (header). I didn’t had this issue before.

I contacted my hosting company to help me find the source of the problem. This is the response i got:

Thank you for your patience, I have monitored the server for a while and the issue occurs when the CPU load is high on the server. The cause of high CPU usage is high wp-admin ajax calls from the application.

The high admin-ajax calls generated by your application are causing load on the CPU due to which the MySQL service is crashing and the website performance is slow.

I would recommend you to install the Heartbeat plugin in all the WordPress applications and configure them as mentioned below:

Modify Activity for Admin Dashboard > Choose frequency between 120 to 300. I would suggest 250 or 200. This will lower your ajax calls, reducing the database connection errors at the backend.

I have also checked and the mail poet plugin is causing slowness on the application due to which the CPU is also getting a bit high. You need to check with the plugin team why it is causing slowness to the site so that the site works well with the plugin.

I managed to setup the heartbeat plugin, but the error persists. So i am hoping i can get this mailpoet issue fixed to continue using it on my websites.

I am using Blocksy theme. How can i get mailpoet work better on my site?

Screenshot in where you can see the mailpoet plugin causing slowness to the site:
https://ibb.co/Dwdf9GM

Website URL:
https://thelionsfocus.com/

Kind regards,

The page I need help with: [log in to see the link]