SquidProxy 0.4.45 + SquidGuard 1.16.18 periods of loss of connection

[SipriusPT]

Hello everyone,

I have SquidProxy 0.4.45 + SquidGuard 1.16.18 running in pfsense 2.4.5, setting up to run only in one network, with outdated machines.

On Squidproxy I 've already disabled Local Cache and this issue seems to have reduced, at least with webpages but still happeans.

On Squidguard I am using Groups ACL for a certain range of IPs, who in this case are those outdated machines. As a default, all web access's are denied, and its only possible to access whiteslisted webservices.

From a enduser perspective, sometimes, Outlooks, Mail Apps from MacOS and IOS, give warnings about unable to connect to server. We have a Office365 Exchange setting up on those devices. For example, during 8 hours per day, 1/3 of the time is unable to connect.
There are also several websites that had the same issue, like there is no internet connection. For example, during 8 hours per day, it occurs 10mins, at least with webpages.

Anyone knows what can be happening, or even what should I try to solve this?

Note: If you need more info feel free to ask.