is there anything interesting in squid's logs?
Here's the end of the log, about the time that we first had issues accessing the sites:
2021/07/03 19:47:02| Current Directory is /
2021/07/03 19:47:02 kid1| Preparing for shutdown after 0 requests
2021/07/03 19:47:02 kid1| Waiting 30 seconds for active connections to finish
2021/07/03 19:47:02 kid1| Closing HTTP port 192.168.86.100:3128
2021/07/03 19:47:02 kid1| Closing HTTP port 127.0.0.1:3128
2021/07/03 19:47:02 kid1| Closing HTTP port 192.168.86.100:8080
2021/07/03 19:47:02 kid1| Closing HTTP port 127.0.0.1:8080
2021/07/03 19:47:02 kid1| Current Directory is /
2021/07/03 19:47:02 kid1| Starting Squid Cache version 3.5.20 for x86_64-redhat-linux-gnu...
2021/07/03 19:47:02 kid1| Service Name: squid
2021/07/03 19:47:02 kid1| Process ID 5784
2021/07/03 19:47:02 kid1| Process Roles: worker
2021/07/03 19:47:02 kid1| With 4096 file descriptors available
2021/07/03 19:47:02 kid1| Initializing IP Cache...
2021/07/03 19:47:02 kid1| DNS Socket created at 0.0.0.0, FD 6
2021/07/03 19:47:02 kid1| Adding domain logicaldevelopments.com.au from /etc/resolv.conf
2021/07/03 19:47:02 kid1| Adding nameserver 192.168.86.100 from /etc/resolv.conf
2021/07/03 19:47:02 kid1| Logfile: opening log /var/log/squid/access.log
2021/07/03 19:47:02 kid1| WARNING: log name now starts with a module name. Use 'stdio:/var/log/squid/access.log'
2021/07/03 19:47:02 kid1| Unlinkd pipe opened on FD 12
2021/07/03 19:47:02 kid1| Local cache digest enabled; rebuild/rewrite every 3600/3600 sec
2021/07/03 19:47:02 kid1| Store logging disabled
2021/07/03 19:47:02 kid1| Swap maxSize 102400 + 262144 KB, estimated 121514 objects
2021/07/03 19:47:02 kid1| Target number of buckets: 6075
2021/07/03 19:47:02 kid1| Using 8192 Store buckets
2021/07/03 19:47:02 kid1| Max Mem size: 262144 KB
2021/07/03 19:47:02 kid1| Max Swap size: 102400 KB
2021/07/03 19:47:02 kid1| Rebuilding storage in /var/spool/squid (dirty log)
2021/07/03 19:47:02 kid1| Using Least Load store dir selection
2021/07/03 19:47:02 kid1| Current Directory is /
2021/07/03 19:47:03 kid1| Finished loading MIME types and icons.
2021/07/03 19:47:03 kid1| HTCP Disabled.
2021/07/03 19:47:03 kid1| Squid plugin modules loaded: 0
2021/07/03 19:47:03 kid1| Adaptation support is off.
2021/07/03 19:47:03 kid1| Accepting HTTP Socket connections at local=192.168.86.100:3128 remote=[::] FD 15 flags=9
2021/07/03 19:47:03 kid1| Accepting HTTP Socket connections at local=127.0.0.1:3128 remote=[::] FD 16 flags=9
2021/07/03 19:47:03 kid1| Accepting NAT intercepted HTTP Socket connections at local=192.168.86.100:8080 remote=[::] FD 17 flags=41
2021/07/03 19:47:03 kid1| Accepting NAT intercepted HTTP Socket connections at local=127.0.0.1:8080 remote=[::] FD 18 flags=41
2021/07/03 19:47:03 kid1| Done reading /var/spool/squid swaplog (0 entries)
2021/07/03 19:47:03 kid1| Store rebuilding is 0.00% complete
2021/07/03 19:47:03 kid1| Finished rebuilding storage from disk.
2021/07/03 19:47:03 kid1| 0 Entries scanned
2021/07/03 19:47:03 kid1| 0 Invalid entries.
2021/07/03 19:47:03 kid1| 0 With invalid flags.
2021/07/03 19:47:03 kid1| 0 Objects loaded.
2021/07/03 19:47:03 kid1| 0 Objects expired.
2021/07/03 19:47:03 kid1| 0 Objects cancelled.
2021/07/03 19:47:03 kid1| 0 Duplicate URLs purged.
2021/07/03 19:47:03 kid1| 0 Swapfile clashes avoided.
2021/07/03 19:47:03 kid1| Took 0.12 seconds ( 0.00 objects/sec).
2021/07/03 19:47:03 kid1| Beginning Validation Procedure
2021/07/03 19:47:03 kid1| Completed Validation Procedure
2021/07/03 19:47:03 kid1| Validated 0 Entries
2021/07/03 19:47:03 kid1| store_swap_size = 0.00 KB
2021/07/03 19:47:03 kid1| storeLateRelease: released 0 objects
2021/07/03 22:40:52 kid1| SECURITY ALERT: Host header forgery detected on local=17.253.75.208:80 remote=192.168.86.164:50067 FD 22 flags=33 (intercepted port does not match 443)
2021/07/03 22:40:52 kid1| SECURITY ALERT: By user agent: SafariSafeBrowsing/16611.2.7.0.4 CFNetwork/1240.0.4 Darwin/20.5.0
2021/07/03 22:40:52 kid1| SECURITY ALERT: on URL: proxy-safebrowsing.googleapis.com:443
2021/07/03 22:40:52 kid1| abandoning local=17.253.75.208:80 remote=192.168.86.164:50067 FD 22 flags=33
2021/07/03 23:11:31 kid1| SECURITY ALERT: Host header forgery detected on local=17.253.75.207:80 remote=192.168.86.164:50072 FD 14 flags=33 (intercepted port does not match 443)
2021/07/03 23:11:31 kid1| SECURITY ALERT: By user agent: SafariSafeBrowsing/16611.2.7.0.4 CFNetwork/1240.0.4 Darwin/20.5.0
2021/07/03 23:11:31 kid1| SECURITY ALERT: on URL: proxy-safebrowsing.googleapis.com:443
2021/07/03 23:11:31 kid1| abandoning local=17.253.75.207:80 remote=192.168.86.164:50072 FD 14 flags=33
2021/07/03 23:41:23 kid1| SECURITY ALERT: Host header forgery detected on local=17.253.75.207:80 remote=192.168.86.164:50084 FD 30 flags=33 (intercepted port does not match 443)
2021/07/03 23:41:23 kid1| SECURITY ALERT: By user agent: SafariSafeBrowsing/16611.2.7.0.4 CFNetwork/1240.0.4 Darwin/20.5.0
2021/07/03 23:41:23 kid1| SECURITY ALERT: on URL: proxy-safebrowsing.googleapis.com:443
2021/07/03 23:41:23 kid1| abandoning local=17.253.75.207:80 remote=192.168.86.164:50084 FD 30 flags=33
2021/07/04 00:10:58 kid1| SECURITY ALERT: Host header forgery detected on local=17.253.67.207:80 remote=192.168.86.164:50093 FD 21 flags=33 (intercepted port does not match 443)
2021/07/04 00:10:58 kid1| SECURITY ALERT: By user agent: SafariSafeBrowsing/16611.2.7.0.4 CFNetwork/1240.0.4 Darwin/20.5.0
2021/07/04 00:10:58 kid1| SECURITY ALERT: on URL: proxy-safebrowsing.googleapis.com:443
2021/07/04 00:10:58 kid1| abandoning local=17.253.67.207:80 remote=192.168.86.164:50093 FD 21 flags=33
2021/07/04 00:41:09 kid1| SECURITY ALERT: Host header forgery detected on local=17.253.75.207:80 remote=192.168.86.164:50101 FD 25 flags=33 (intercepted port does not match 443)
2021/07/04 00:41:09 kid1| SECURITY ALERT: By user agent: SafariSafeBrowsing/16611.2.7.0.4 CFNetwork/1240.0.4 Darwin/20.5.0
2021/07/04 00:41:09 kid1| SECURITY ALERT: on URL: proxy-safebrowsing.googleapis.com:443
2021/07/04 00:41:09 kid1| abandoning local=17.253.75.207:80 remote=192.168.86.164:50101 FD 25 flags=33
2021/07/04 01:10:59 kid1| SECURITY ALERT: Host header forgery detected on local=17.253.75.207:80 remote=192.168.86.164:50107 FD 11 flags=33 (intercepted port does not match 443)
2021/07/04 01:10:59 kid1| SECURITY ALERT: By user agent: SafariSafeBrowsing/16611.2.7.0.4 CFNetwork/1240.0.4 Darwin/20.5.0
2021/07/04 01:10:59 kid1| SECURITY ALERT: on URL: proxy-safebrowsing.googleapis.com:443
2021/07/04 01:10:59 kid1| abandoning local=17.253.75.207:80 remote=192.168.86.164:50107 FD 11 flags=33
2021/07/04 01:41:15 kid1| SECURITY ALERT: Host header forgery detected on local=17.253.67.208:80 remote=192.168.86.164:50115 FD 32 flags=33 (intercepted port does not match 443)
2021/07/04 01:41:15 kid1| SECURITY ALERT: By user agent: SafariSafeBrowsing/16611.2.7.0.4 CFNetwork/1240.0.4 Darwin/20.5.0
2021/07/04 01:41:15 kid1| SECURITY ALERT: on URL: proxy-safebrowsing.googleapis.com:443
2021/07/04 01:41:15 kid1| abandoning local=17.253.67.208:80 remote=192.168.86.164:50115 FD 32 flags=33
2021/07/04 02:11:34 kid1| SECURITY ALERT: Host header forgery detected on local=17.253.75.208:80 remote=192.168.86.164:50129 FD 24 flags=33 (intercepted port does not match 443)
2021/07/04 02:11:34 kid1| SECURITY ALERT: By user agent: SafariSafeBrowsing/16611.2.7.0.4 CFNetwork/1240.0.4 Darwin/20.5.0
2021/07/04 02:11:34 kid1| SECURITY ALERT: on URL: proxy-safebrowsing.googleapis.com:443
2021/07/04 02:11:34 kid1| abandoning local=17.253.75.208:80 remote=192.168.86.164:50129 FD 24 flags=33
2021/07/04 02:41:34 kid1| SECURITY ALERT: Host header forgery detected on local=17.253.75.208:80 remote=192.168.86.164:50137 FD 28 flags=33 (intercepted port does not match 443)
2021/07/04 02:41:34 kid1| SECURITY ALERT: By user agent: SafariSafeBrowsing/16611.2.7.0.4 CFNetwork/1240.0.4 Darwin/20.5.0
2021/07/04 02:41:34 kid1| SECURITY ALERT: on URL: proxy-safebrowsing.googleapis.com:443
2021/07/04 02:41:34 kid1| abandoning local=17.253.75.208:80 remote=192.168.86.164:50137 FD 28 flags=33
2021/07/04 03:11:39 kid1| SECURITY ALERT: Host header forgery detected on local=17.253.75.208:80 remote=192.168.86.164:50155 FD 26 flags=33 (intercepted port does not match 443)
2021/07/04 03:11:39 kid1| SECURITY ALERT: By user agent: SafariSafeBrowsing/16611.2.7.0.4 CFNetwork/1240.0.4 Darwin/20.5.0
2021/07/04 03:11:39 kid1| SECURITY ALERT: on URL: proxy-safebrowsing.googleapis.com:443
2021/07/04 03:11:39 kid1| abandoning local=17.253.75.208:80 remote=192.168.86.164:50155 FD 26 flags=33