Secure-Adblocking-DNS VS dnslookup

I used stunnel (followed instructions from here).

I test that IP with https://github.com/ameshkov/dnslookup and it doesn't respond to Do53, DoH nor DoT.

In both FF 113 and FF 114, the proper DoH address works fine, including https://1.1.1.1/dns-query, also try with the servers at https://github.com/curl/curl/wiki/DNS-over-HTTPS, you can verify them through https://github.com/ameshkov/dnslookup

On Windows just extract https://github.com/ameshkov/dnslookup/releases/download/v1.9.1/dnslookup-windows-amd64-v1.9.1.zip and run the terminal from that folder.

So does Chrome says you have a valid cert, or not? That error message comes from AGH, not from Chrome. If Chrome says your cert is valid, then there's no issue. Verify that the DoT (if you use them, if not you can just rely on Cloudflare cert) works with https://github.com/ameshkov/dnslookup

I'm using Technitium, and it requires converting cert to pkcs12, and I think something is wrong here — dnslookup keeps telling me that "tls: failed to verify certificate: x509: certificate signed by unknown authority".

What is your AGH upstream address, and how did you set up Quad9 & Cloudflare? Using dnslookup, compare the result of querying mangadex domain against your AGH instance and Quad9.

Do you have a pc/laptop at hand? Try checking with https://github.com/ameshkov/dnslookup if the DoH/DoT addresses of AdGuard work correctly (ie, filter doubleclick.net etc)

If you directly lookup using https://github.com/ameshkov/dnslookup, does the delay still happens? If not, could be browser/OS caching.

I used https://github.com/ameshkov/dnslookup and the endpoints in https://adguard-dns.io/kb/general/dns-providers/#cisco-opendns, all of them resolve my domain correctly. Could be region specific though.