You're running Wheezy with an unsuporrted older version of dnsmasq, both of which are not supported by the latest Pi-hole. I would look at updating your OS first before running the latest version of Pi-hole.
As requested I have created a new debug token i3kwhc9nhh
I can see some errors regarding SQLite is not installed, could this be the issue?
I don't think the router forward to another DNS server because I can see all ads blocked. But anyway, I have just filled the second field with the pi-hole IP address and will see if that makes any differences.
And yes, by now it has been few days since I did the upgrade.
I can see latest Raspbian is based on Stretch. If being on Wheezy definitely is the issue, I will reinstall my Raspberry Pi.
So reinstalling might be a good idea. The issue with Wheezy is that FTL cannot analyze the logs generated on Wheezy any more as they are in an old format we don't support any more (dnsmasq hasn't been updated for several years on Wheezy). While blocking still works, FTL cannot generate any statistics as the query details cannot be analyzed.
[i] Neutrino emissions detected...
[✓] Pulling blocklist source list into range
[i] Target: raw.githubusercontent.com (hosts)
[✓] Status: Retrieval successful
[i] Target: mirror1.malwaredomains.com (justdomains)
[✓] Status: No changes detected
[i] Target: sysctl.org (hosts)
[✓] Status: No changes detected
[i] Target: zeustracker.abuse.ch (blocklist.php?download=domainblocklist)
[✓] Status: No changes detected
[i] Target: s3.amazonaws.com (simple_tracking.txt)
[✓] Status: No changes detected
[i] Target: s3.amazonaws.com (simple_ad.txt)
[✓] Status: No changes detected
[i] Target: hosts-file.net (ad_servers.txt)
[✓] Status: No changes detected
[✓] Consolidating blocklists
[✓] Extracting domains from blocklists
[i] Number of domains being pulled in by gravity: 145404
[✓] Removing duplicate domains
[i] Number of unique domains trapped in the Event Horizon: 122436
[i] Nothing to whitelist!
[✓] Parsing domains into hosts format
[✓] Cleaning up stray matter
[✓] Force-reloading DNS service
[✓] DNS service is running
[✓] Pi-hole blocking is Enabled