Problem: KDE Connect is unable to see devices either from my phone or from the laptop. The reason being UFW on my laptop. I had to manually allow ports in UFW for getting KDE Connect to work. Proposed solution: Preconfigure firewall (iptables, ufw or something else) by allowing KDE Connect ports during KDE environment installation. We can use iptables for this purpose as it comes pre-installed on many distros by default.
*** This bug has been marked as a duplicate of bug 358440 ***