Hi,
Do you have any firewall , Antivirus or anti-malware install on your computer ?
If yes, be sure to whitelist the domain ultimapsobb and also the ".exe"directly, depending of the software used.
I got this issue, it was related to my malwarebyte software.
For example, on my computer at my work, the url is seen as a Trojan :
It's a false positive, but it'll block connection until I permit it manually.
Can we have a screenshot of the blocking page ? That can help us to know the reason of the block.
Are you familiar with wireshark ? if you are able to capture packets during a launcher connection attempt, I should be able to take a look at the capture and tell you which device in your network is blocking you.