NAT Reachability Notes
NAT can affect how a destination sees an address and port. A small, repeatable check helps separate routing issues from application settings.
Suggested workflow
Record the client network and test time.
Compare the observed public address with the local context.
Test the destination port from the same environment.
Repeat from another connection when results differ.
For a browser-based NAT check, visit NAT Checker. Keep the result with a timestamp so the test can be reproduced.