I have a Windows 2016 Standard server I created a couple months ago and then joined it to a new AD I created. Since then when I log in as the local administrator, I'm unable to open the Action Center, nor can I left-click on the Windows start icon (no response), nor is the search icon functional. This feels like an AD screwup on my part somehow but I'm not sure what I would have done. Admittedly my skillset as an AD administrator is at the bottom of the barrel.
Any suggestions on how to diagnose this? Most of the research I've done concerns other issues that don't appear to be relevant to this one.
I do see a number of errors in the Application event log (Cortana can't start, ShellExperienceHost can't start, etc.).