504 Gateway Time out trying to access Staff-Member page

Hi,
Since updating the plugin today I’ve been unable to access the overview page for the free version of the plugin. This is the page which displays all the individual staff member posts. When I click on it the URL (https://<mywebsiteURL>/wp-admin/edit.php?post_type=staff-member) I get a 504 gateway timeout.

It’s only this page that’s having this error. The add new staff member and staff categories can both still be accessed and the content is still displaying on the front end. However I’m unable to effectively manage the content in the CMS. I had to use PHPMyadmin to publish a draft page today which isn’t the best way to manage this.

I’ve tried a clean install of the plugin and deactivating everything else to check for conflicts and it’s still experiencing this problem.

Is this a slug issue? I’m at a loss as to how to fix this and I don’t want to have to uninstall as it’s been a really great plugin.

Thanks for any advice!