I had this issue. Solved. I have to use dns 1.1.1.1 whenever I use steam now to download so it won't have no internet error. But why? I used Steam normally before and now I need this. Is it because I used 1.1.1.1 and ProtonVPN before which changed my IP or DNS? (Sorry Im new to these topics).
Source: r/steamsupport · by /u/Appropriate-Help-982