Can't load the Shield admin pages, "DevTools failed to load SourceMap" error

Sometimes it can happen that you are unable to use the Shield plugin because none of the settings (admin pages) are being loaded. No matter which tab you open, you get stuck with an endless "loading ..:" screen.

When you check web console, you see the following errors:

Trying deactivating the plugin or reinstalling wont help, and this is why...

Firstly, these "errors" are not actually errors that would affect your web page loading. They are specific to the DevTools which developers might use to debug, and update code.

The reason you're getting the constant "loading" text is because these admin pages are loaded over AJAX and there is output on your site that is interrupting the AJAX response. Likely it's a PHP notice, or error that's being output by another plugin or theme.

What is required here is to find the plugin (or theme) that's causing the output/error. To do this:

1. Disable each plugin on your site, 1 at a time and test whether you can load the Shield admin page.
2. After you test loading Shield admin pages, you can re-enable the plugin.
3. Once you disable a plugin, and the admin loads successfully again, you've found the plugin causing the problem.

If no plugins solve it, try perhaps switching your theme to TwentyTwenty, or something like that.

Basically, somewhere, something is output text that's interrupting your AJAX calls to your site.