This could probably be a mismatch in between your App10 UPD and the TAS version you have installed. Make sure you have upgraded the TAS to the correct version which was delivered with your current Apps-10 Update OR with the latest Mobile Framework (FNDMOB) delivery you have installed. 

Thanks Pubudu.  Is there a spreadsheet that outlines IFS version and compatible TAS versions?

The Touch Apps Server in Apps 10 is delivered in each Update. When you install an Apps 10 UPD you should also install the delivered Touch Apps Server.

The Touch Apps Server can be found in the manualdeploy\install folder in your Build Home.

I know this is an old post, but I am having the same problem and I am positive that I applied the TAS installer that came with my most recent UPD. Does anyone know of a way to extract the version information from the Touch Apps installer? Or do you rely on the version being reported in the “Customer Portal”?

Furthermore, I had an existing instance of Touch Apps in a test environment that I upgraded from UPD18 to UPD20, then applied the manual deploy installer (10.20.497.0 reported in “Customer Portal”). This instance works just fine as I am able to connect via mwo Maintenance 10, but the “new” instance using all the same software and a similar configuration throws the 404 error.