White screen after login

The white screen can appear because of different reasons.
The most simple way to that can solve the issue is to empty your cache.
Another thing is to use the WordPress debug function. Add the following code to the wp-config.php file:

1 error_reporting(E_ALL); ini_set('display_errors', 1);
2
3 define( 'WP_DEBUG', true);

A third thing you can do is to re-install a fresh copy of WordPress. It is a more radical way, but sometimes it helps.

I can load it for another wordpress site – so its not my brower I don’t think.

Do steps 2 and 3 mean uplioading via the ftp etc?

Sorry I am abit of a novice!

Hi sorry to bump this Im just really lost

Thanks

Yes, you may edit wp-config.php file through FTP or filemanager in your cpanel.
I hope it helps.

Hi I deactivated plugins to try

And get the login type page but am seeing the website if that makes sense- but when click dashboard I now get this:

W3 Total Cache Error: some files appear to be missing or out of place. Please re-install plugin or remove /websites/123reg/LinuxPackage22/ge/ne/ra/generatorservicing.com/public_html/wp-content/advanced-cache.php.
Fatal error: Call to undefined function wp_json_encode() in /websites/123reg/LinuxPackage22/ge/ne/ra/generatorservicing.com/public_html/wp-admin/includes/misc.php on line 682

ive tried deactivating w3 total cache and that does not help

ive also done a reinstall of w3 and that has failed to help. It has now left the website totally blank to viewers if I leave the plugins enabled. So I currently have plugins called. plugins.deactivated so that people can see the site – but I am still unable to login etc!