It sounds like you are trying to setup the thin client to print via an SMB shared printer on a 2016 print server?
It looks like the old WYSE KB is in transition to Dell and some of the links are missing, but this KB article will help you.
I did find that in order to print via a 2016 print server you have to adjust the server to allow SMB 1.0 communication. The following MS article will help with how to enable it.
In my experience, the SMB printing through a print server has been much more reliable than LPD. Just remember, with ThinOS, the SMB share names CANNOT have spaces in them. Also, the path needs to be"\fqdm.whatever\PRINTSERVER\SHARED-PRINTER". If you are configuring from WMS, it will automatically place the first single "\" and the "\" between your print server name and the shared printer name.
"\\" paths will work if you set that manually in the ThinOS interface, however trying to use "\\" in WMS settings will result in them getting stripped and replaced with "\". That's why I suggest using the FQDM with the single "\".
Also, make sure you use the same spelling for your printer driver as it has in the print server (spaces are ok here).