chat functionality is not working on 17.3.0.8 Service Point
check collabMS log
INFO - 2021-08-26 19:57:02 [c.c.c.bot.controller.BotController] - NLU agent server url:http(s)://<nlu_server>:<port_number>/<optional_path_if_any>
Release : 17.3
Component : SDM - Other
check if the nlu server is not configured in sdm
Go to Administration Tab -> XFlow Interface -> General
Search for the option " va.bot.nlu.server.url " and set the value as your rasa URL
then Restart xFlow services.