I'm aware that there is a thread on this in the 19.1 Testing Forum (https://support.dataaccess.com/Forum...a-2-Error-5122) but as this forum is now locked I am unable to add to it.

So just to say, I'm also battling with this, but with no real joy.

19.0 WebApp is running just fine. Migrated to 19.1 and hit this error. Have tried all the things in the thread with little joy. Or rather, if I come up with a completely new virtual directory name then I can make it work - so I have this as a workaround - but if rename it back again I hit the error. Nothing quirky about the migration to 19.1 - migrated in the expected manner just as I normally would.

I've checked all the handler mappings in IIS and they're all pointing at the 19.1 bin folders, so that's ok. But deleting and re-registering the WebApp doesn't resolve the problem. The only way I can currently side-step the error is to come up with a new virtual directory name, which is ok, but this means using a virtual directory name that no longer matches the product name so it isn't ideal.

Anyhow, I'm not particularly expecting a suggested fix here that isn't already one of those mentioned in the other forum, but just thought to log this so as to add to the overall picture.