I took over as admin of my department's SharePoint 2016 site at the beginning of the year. I edited a site workflow to add a few more individuals to the notification email that goes out. Up until that point, the workflow ran as scheduled. Ever since I made that edit, the workflow cancels and errors out. I get two notification emails. One states that the workflow was canceled by System Account and a 2nd email states that the workflow errored, "Failed to start". To test this, I built a workflow that just sends a notification email to me. There are no other parameters in the workflow. If I run it manually, the notification goes out. But if I schedule it, I get the two emails I specified above. I had one of my peers do the same thing and get the exact same results.
Is it possible there are permissions somewhere specifically affecting the ability to have scheduled workflows run? I've googled this and find a few results but they all link to a "fix" articel from a few years ago with instructions on clearing the designer cache on SP2010/2013 but nothing on 2016 and I can't find a way to do that based on the instructions provided. Any help is appreciated.