Squid Proxy working on some networks and not others

[ThanosK]

Good day,

My setup is as following :
pfsense with squid only, not much setup done to pfsense as i only need it to function as proxy.

In my company we have about 20 site to site VPNs all running with the same rules.
What i need is to apply proxy setting on a few windows computers running on those VPN sites.

When i setup squid proxy on pfsense , on some computers it appears to work properly, while on others webpages keep loading forever…
Communication appears OK between those networks and pfsense.

Is there anything i can check on pfsense or should i be looking at the VPN setup?

Any assistance/idea would be helpful

Thanks in advance