I had this error on my WordPress site, but I managed to resolve it, so I'm writing this down as a memo.
Error message: Allowed memory size of 268435456 bytes exhausted (tried to allocate 14684160 bytes)

The server environment is Lolipop. The error message is that PHP memory is insufficient and the page cannot be displayed.

This is the procedure if you are using the "module version." First, change to the "CGI version" and then proceed.

Log in to Lolipop and go to PHP settings

First, log in to Lolipop and go to PHP settings.

Open php.ini settings

This explanation will be for the CGI version, so please make sure that the version you are currently using is CGI before proceeding.

Enable php_value and php_flag

Turn on Enable php_value and php_flag to prioritize the .htaccess settings.
Once you turn it ON, click the button to set [php.ini].

Edit the .htaccess file

Next, access Lolipop FTP and edit the .htaccess file.

Here is the .jhtaccess file. Click on it to open it for editing.

This is a very important file, so please [download] it before touching it.
If your site no longer displays after editing, please upload the downloaded file and restore it.

Add this code to the top and save it.
This time, since the site was heavy, I added code to increase it to 1024M.
Change the numbers depending on your environment.

php_value memory_limit 1024M