SC won't connect from certain sites

[Encrypted]

Hello, I have been using SC for a few months now. I have ports forwarded on my end so the SC client can call home fine. I have the system being used in 15 different sites. For some reason certain sites just won't work. I have checked and checked the firewall settings on the remote end. I have the same routers being used with the same settings at different sites and it seams to work fine. I can monitor outbound traffic from the remote sites and the traffic is leaving there properly. What could be causing some sites to not connect back home? Any Ideas?

Thanks,

[YY]

What did you use for the host inside the helpdesk.txt (fixed IP or DynDNS host name)?. Sometimes those free dynamic DNS services do not reflect the change of your real IP promptly.

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We have a static IP at our location and I have 2 different terminals that I have forwarded different ports to.

[redge]

on some site, it there the SC corrupted ?
did you try to replace it ?

all your customer who have problem connection with SC, is it use same Internet Service Provider ?
some isp block traffic port above 1024, like France