You again didn't write if you try this on local server or not, or you use Apache or IIS, neither PHP version.
- try direct login to admin area: /e107_admin/admin.php
if it didn't work, go to phpMyAdmin, find your user account and change your password (write it to the password field and use md5 hashing)
My guess is that you have problem with cookies, with all that GDPR stuff and problem is in your browser.
You are not only one, but it doesn't happen to me. If nothing helps, only core developers can help.