When certain PC's are trying to access http (port 80) at seemingly random times, they are unable to. With sites taking a long time to load or outright failing to . It only seems to affect outgoing (through the firewall) http traffic and nothing else, eg https (port 443) still works. Internal HTTP is unaffected.
The scope of the issue is over 2 different VLANS/Subnets but does not affect all pc's on those VLANs/subnets.
The only fix is for the user to restart the local PC at this time.
Checked locally on the machines affected with all sorts of various attempts to fix.
Restarted any and all networking gear.
Ran wireshark packet traces.
Although we have performed WS traces we don't currently have the experience to identify issues, therefore any pointers would be greatly appreciated.