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I've got a client whose QuickBooks updates fail on an XG125 with XG OS 17.0.3 MR-3 unless we disable http scanning and IDS on the firewall rule. The firewall and web filter do not log any denies. I've also seen some odd behavior with streaming installs of Office 365 and Dropbox on this same firewall.
at least for SG you need these lines with the additional HTTPS part.
I had a similar problem. I added the following under Web->Exceptions as a URL Pattern Matching exception:
XG may need it also but this solved the issue on SG
with the lines originally recommended it did not work.