After the update, Vivaldi stopped sending HTTP 3 requests.

pda

After the update, Vivaldi started sending requests for the video player using HTTP 1.1 protocol.
The old version sent requests via HTTP 3.
How can I fix this so that requests are sent via HTTP 3?!

DoctorG

@pda I can not test at this time as i have no device for QUIC/H3. But i checked with website https://http3check.net/about and Vivaldi 6.8.3381.50 and 6.9.3425.3 (both installed with deb package from vivaldi.com) running fine with QUIC/H3 on Windows 11 23H2 + Debian 12 KDE + Ubuntu 22 LTS GNOME.

play nice with protocol H3 at https://www.youtube.com/watch?v=fMTTUAlC14k as i can see in Developer Tools → Network.

As i can see you try to access a video where you got blocked and that caused a Error 403.

DoctorG

@pda Check without extensions which might cause a block of H3 in Youtube videoplayer
Run in shell:
vivaldi --disable-extensions &

And check your Vivaldi Ad/Tracking Blocker and update RU Adlist in Blocker if not done.

pda

@DoctorG , think found a solution, I switched the flags to enabled.
#enable-quic
#enable-tls13-kyber
before it was default

With only #enable-quic enabled, it didn't work.
running without extension and with the built-in blocker switched off didn't work either.

Now the request goes through http 3 and it works.
Thanks