Bug Report OBS doesn't capture audio

I read many posts about this problem but I wasn't able to fix it.
I use OBS only to record webinars and the audio doesn't work. I've used it for a long period without any problem. Two weeks ago I changed my pc and it doesn't work anymore. I spent a fortnite looking for a solution but nothing.
I have a Lenovo, I7, 16GB RAM, WINDOWS 10, x64, realtek High definition audio. Drivers are updated to the last version.
Thanks in advance for your help.