Every published troubleshooting guide, with the newest first.
268435456 bytes is a 256 MB PHP limit. If you already raised it, find the plugin or task using the memory before raising it again.
134217728 bytes is a 128 MB PHP memory limit. Raise it to 256 MB in wp-config.php, your hosting panel or php.ini, then confirm the new limit is active.
A printer shown as Offline in Windows is usually a connection problem, a stuck print queue or the Use Printer Offline setting. Check these in order.
The PHP allowed memory size error means a script needed more memory than PHP allows. Raise the limit safely, then find what is using too much.
The WordPress critical error is usually a plugin or theme problem. Use the recovery email, read the debug log, then deactivate plugins and themes to find the cause.