I cannot log into my gmail account on my mac, am using High Sierra version 10.13.6, no more updates available. Mail keeps asking for a password, tried verything but still cannot login

Can you log in to gmail.com? Mail in High Sierra may be too old to comply with Google's recent authorization requirements.

You may need a browser other than Safari as well such as Firefox or Brave to log in to gmail.com

You're welcome. Until someone comes up with a better answer I guess you're stuck using webmail.