Box, Dropbox, Skype, TortoiseSVN all failing

[GingerPatcher]

Every day my email notification is telling me the updates for Box, Dropbox, Skype and TortoiseSVN have failed. They all fail with the same error "The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel."

Everything else is fine, it's just these four, always these four.

Thanks.

[Justin Chalfant (Patch My PC)]

Sorry for the delay, this would be a firewall issue.

[GingerPatcher]

Thanks for the reply. Any idea where to start looking? Particular log file? It seems odd because it's just these that are affected, everything else downloads fine.

[Justin Chalfant (Patch My PC)]

Try downloading the URL that's failing in a browser to see if you get an error from your web filter.