App generator uses HttpCache internally for the past 10 yeara. The latest windows 10 update raises an exception when trying to access HttpRuntme.Cache object.
We have refactored the code to capture the exception. The fix is in the next update.
This seemed to be an IIS problem. I had the same problem with 1903 this week and fixed it by going to Windows Programs / Features and turning on Internet Information Services. This then copied nativerd.dll into inetsrv folder (in system32 and systemwow64)
Hasn't affected iis express. Everything now working fine in COT.
I'm assuming (probably wrongly knowing me) that nativerd.dll was previously in the inetsrv folder before Windows 10 1903