Months before I arrived at this job, my current organization contracted a 3rd party to build an Out of Office calendar that essentially was going to be used as a requested time off kind of system. The user would click a tile in the calendar and add a request for time off, then the workflow would send an email to the supervisor for processing. It uses a "pending" & "approved" status system.
My supervisor says the whole workflow is unreliable/doesn't work. If we click on "IT Test", we are redirected to a "page not found" page. Furthermore, when I try to edit the workflow I get an error saying it can't be customized within the browser. I've heard before that the original user who created the workflow must be the one to edit it? Is this true? Any possible solution would be greatly appreciated.
Btw, this is SharePoint Online - Classic