Are you seeing this type of error on your site?
This error is caused due to insufficient amount of memory available for your WordPress code.
All the sites are different and since they are different, the memory they require to for their PHP code will be different (some sites requires more memory than other). WordPress by default tries to increase the PHP memory limit upto 64MB but if your site requires more memory, you need to do the things as mentioned:
You need to open wp-config.php file and paste the code below.
define( 'WP_MEMORY_LIMIT', '256M');
Note: You need to paste this code before the line that says, ‘That’s all, stop editing! Happy blogging.’
Note: the code above increases your memory limit to 256 MB
If your problem is still not solved, you need to contact your hosting service provider.