Below are few things that you can do to try to fix the WSoD

1. Check the PHP memory limit. To function properly, WordPress requires a specific amount of memory. The WSoD may occur if your PHP memory limit is too low. In the control panel for your hosting account, you can increase the PHP memory limit.
2. Deactivate plugins: A plugin might be the WSoD’s cause. Disable all of your plugins and check to see if the problem is fixed to troubleshoot this. If so, you can begin turning on plugins one at a time to identify the problem causing the plugin.
3. Change to the default theme: It’s possible that the custom theme you’re using is what’s causing the WSoD if you’re using one. Change to the default theme and check to see if the problem is fixed to troubleshoot this. If it is, you can try going back to your custom theme to try and figure out which specific piece of code is causing the issue.
4. Update WordPress.: Regularly, new versions of WordPress are released. These updates frequently include bug fixes that might help in WSoD resolution. Verify that WordPress is installed and updated on your system.
5. Check index file: Corrupted index file may also cause this error.