“White screen of death” or similar problems usually indicate a ‘fatal’ plugin problem.
You should look at the error.log file (usually in your site root, but could also be in the wp-admin folder) via your FTP/host File Manager, and look at the latest error. It will usually tell you the file that caused the problem.
If it is a plugin folder, temporarily rename that folder via FTP/File Manager and reload the admin page. It should come up.
Then you can investigate the plugin via it’s support page (better there than here).
You can also post the error here, but I suspect a plugin is causing the error.