1939686 - Length of X exceeds maximum length 4, specified with tt:maxLength

Error : Length of X exceeds maximum length 4, specified with tt:maxLength on consuming a webservice. (X= a number)

This is because ByDesign system will be receiving the value in request XML tag as follows:

X with a space in the end. So the BYD considers it over limit (more than 4).
or X again coming up with a space in between.

You can remove the space from the request XML structure and send the data back again to the ByDesign system.

KBA , length of x exceeds maximum length 4 , AP-RC-ODF-BYD , OData Framework and Console (ByD) , How To