No internet with pihole DNS

[AlbertCamus42]

This problem seems to be pretty common. But, I have not found other topics with the same errors after running pihole -d.

Expected Behaviour:

Having access to internet with Pihole as the primary DNS
OS: DietPi ( But I had the same issue before with Rasbian Pi Lite 4.19)
Hardware: Pi zero w
Pi-hole: v5.0

Actual Behaviour:

I have no internet access from the clients. The problem is the same if I change the DNS in the router or in just a specific client. However, I still have access to the local network.

I ran the command pihole -d and I suppose that the problem is linked with this error you can see multiple times in the debug token:
"FATAL: Trying to access upstream ID 0, but magic byte is 0"

Debug Token:

[3zrzuepmb8]

What do you think of it guys?

[Bucking_Horn]

Your debug log shows an inconsistency for your configuration:
Pi-hole isn't aware of any upstream destinations to forward non-blocked queries to, despite you having configured two such destinations:

*** [ DIAGNOSING ]: Setup variables
    PIHOLE_DNS_1=1.1.1.1
    PIHOLE_DNS_2=1.0.0.1

*** [ DIAGNOSING ]: contents of /var/log
-rw-r--r-- 1 pihole pihole 4564 Jul 12 19:10 /var/log/pihole-FTL.log

   -----tail of pihole-FTL.log------
   [2020-07-10 01:07:19.402 228] Database successfully initialized
   [2020-07-10 01:07:19.416 228]  -> Known forward destinations: 0

This may be caused by a time mismatch for your RPi, especially if you were using DNSSEC (which seems not be the case at the time you submitted your log).
Anyway, your log shows your time to have been off by a few days:

   [2020-07-12 19:10:40.360 234] WARN: getOverTimeID(1594577700): 541 is too large: 1594253100

Check your RPi's time zone information and adjust time as necessary, e.g through sudo raspi-config, and see if your issue persists.

[AlbertCamus42]

Okay, so I adjusted the time. The errors related to the time mismatch have disappeared from the debug log. However, I still have my original problem and new errors have appeared in the debug log. It is related to /var/log/lighttpd and consists of PHP warnings. I don't know if this is related to my original problem or not.

New token:
[6z1q09699a]

[AlbertCamus42]

Update: from my understanding those PHP errors concern the web server and thus are not linked with my problem (aka no internet access). Therefore, I don't know what could possibly cause my problem.

Also, I forgot to add one detail. While having the Pi setup as the DNS server in my router, clients fail to execute ping and nslookup commands. However, the Raspberry pi can still execute successfully those commands and have access to the internet.

Edit: Here is the token
[zvqjdu75jj]

[jfb]

Please post the token generated by

pihole -d

or do it through the Web interface:

Tools > Generate Debug Log