Upgrading lubuntu from 20.10 to 21.04 made no access to internet with connected wifi

Hello, I have upgraded my lubunto and now I have no access to the internet.
I have tried many things but still the problem temains.

In the recovery mode I can set dns in /etc/resolv.conf and I can access internet. But in the normal mode, I can sometimes ping to a website but as soon as I open firefox or try apt update no internet access.

If there is a command output I should provide, just let me know.

Have you posted about this on askubuntu? (if you have a link is useful as there is a very similar post but more detail was provided there).

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