Welcome to ChiefDelphi!
The
FMS Whitepaper may have some guidance.
To clarify - you're trying to connect to the various services on the robot which are available, but doing so disables the robot? I haven't seen this behavior before, but I also don't program robot code.
In the past I've programmed custom socket code over the allowed ports (5900-5910 iirc). I've done this with Java code (relatively straightforward if you say everything is an array of doubles). This year the kids setup a node server in the classroom on those ports. Then the robot wrote data to the node server, and clients could connect from any laptop on the robot's subnet to that node server. This has worked live on the field in the past. In 2016 we had to use NetworkTables to get any custom data off of the robot during a match.