problem with connecting private blazingseollc proxies port 444

i just bought some private proxies from blazingseollc they are user authenticated, login & password, after testing them multiple times & not working on the vps i & blazingseollc tested the proxies & they are working ok.
i have tested them on gsa ser using whatismyipaddress, bing, google scrape etc etc
the proxies are using port 444 which i thought might be the problem
the vps host has done loads of things to try & get it working such as :-
-opened the port 4444 in windows firewall

-whitelisted server IP in router

-whitelisted the IP and open port in server

but has anyone got any ideas because i thought someone might have come across this before
the proxies are definitely in the correct format   ip:port:user:password
ive tested the proxies in gsa ser dozens of times & still not working