I've been researching on the web for quite some time now, and while others have reported the similar error message *"A Microsoft SharePoint Server State Service error occurred while processing your request. For more information, contact your server farm administrator.
Click Start over to load a new copy of the form. If this error persists, contact the support team for the Web site.Click Close to exit this message."*
The solutions seem to be that there is a look up choice field or a data connection that has gone awry. This form was working fine until a day or so ago, and there are no data connections - only the one for the submit (which is correct - I've checked it) and the choices data field which is built into the form - it doesn't go anywhere to get the choices they are manually added to the field itself.
The thing is, once you fill in the form and hit submit, it will "sending data to the server" for the prescribed time out period, then 'fail' with the message above - however the data is submitted to the library and the workflows fire as normal.
Correlation ID returns nothing except
Request URL: .../org/par/as/_layouts/15/Postback.FormServer.aspx and when I network trace, it's giving me a 401 / Unauthorized... but it's been working before and none of the logs I can find make mention of which account is unauthorized. I've checked the WFE and the SQL.. nada.
The only server changes I know of are a WFE reboot..
Was hoping for some ideas from the community before I rebuild...