Critical error

That file, though in the WP core folders, is not a core file. There’s some evidence that this may be due to the Google Authenenticator plugin. Are you using that?

Yes, I’m using Google Authenenticator plugin.

I recommend asking at https://www.ads-software.com/support/plugin/miniorange-2-factor-authentication/#new-post so the plugin’s / theme’s developers and support community can help you with this.

For the nonce, I suggest you try deleting it. Via FTP or your hosting control panel, delete the directory wp-content/plugins/google-authenticator.

Thanks – I’ll try that.