My campaigns list page does not load properly
In most cases, this problem is triggered by the grid columns in the campaigns list, which show stats (see image below).
What happens is that in order to show the stats, MailWizz has to query the database in complex ways, which can be very resource intensive and if the server is not configured to allow this, you will end up with a broken page.
To avoid this, MailWizz uses a cache system where this information is stored and retrieved as needed, which makes access very fast and easy on resources.
However, sometimes, this cache cannot be populated and then MailWizz must go back and do the resource intensive step.
In order to avoid this problem, first thing you can try, is to increase PHP's memory limit.
By default, PHP's memory limit is set to a value less than, or equal to 128M, which is not always enough for resource intensive tasks, so increasing the memory limit to 256M or more, can help.
You can check this article and this one, while they don't specifically talk about increasing the memory limit for PHP, they give enough info for you to understand how to do it.
Remember to restart your web server and/or PHP-FPM after you apply the changes to your PHP configuration.
If the above does not solve the problem, the next obvious solution is to simply not show the columns with stats, and MailWizz gives you this option, it allows you to toggle between the columns visibility:
If removing those columns is not an option, then MailWizz provides a console command to help you warmup the cache for the stats shown in those column.
You can find more details about the command here.
We recommend adding this command in your cron jobs list and run it each minute so it keeps your cache warmed up all the time.