Verify Connection fails > Checking server callbacks

Setting up my new work laptop (Windows 10, with the latest updates), I got
RDi 9.6.0.3 and iSphere 3.3.0 installed. FWIW, I did not import my
workspace from the old laptop. Set up a new connection to our development
box, and did Verify Connection:

Connection to Central service . . . . . . . . .successful
Connection to Command service . .. . . . . . .successful
Connection to Data Queue service . . . . . .successful
Connection to File service . . . . . . . . . . . .successful
Connection to Record Access service . . . .successful
Connection to Signon service . . . . . . . . . .successful
Checking PTFs
. Rational Developer for i . . successful
Checking server callbacks
. Checking callback to RSE daemon
. Callback to <My laptop's IP address> on port 4300 failed
. Callback to <my laptop's "computer name", i.e. <MyPcName>.<domain>.com
on port 4300 failed

My old Windows 7 laptop has the same RDi and iSphere installed. Both are
connected to the internal network here in the office. On the old laptop,
the callback succeeds on the IP address and doesn't bother with the
callback using the computer name.

Google wasn't my friend. I checked the RDi forum in the developerworks Rdi
Hub, found a reference to this problem which suggested changing the port
number from the default 4300 to something else, but not sure I want to
impact other users who aren't having problems.

I'm guessing maybe there's a firewall issue, but no idea how to proceed.
It would be nice if these errors had some link to a help page that would
give more information that might lead to a resolution. I imagine I'll
eventually have to ask our PC support folks to resolve this, but the more
useful information I can give them, the better.

- Dan