Can't log in after site import

New wp installation, imported the existing site with all-in-wp migration. The site works quite well, but I can’t log in - I get: http://testfly.dev/wp-admin/testfly.dev/wp-admin/upgrade.php?_wp_http_referer=%2Fwp-admin%2F which doesn’t exist of course.
Any ideas?
Thanks

Did you make a search and replace in the DB to set the correct url? Check in you options table if the url is correct

The site runs fine, and in the options table, I see on both locations testfly.dev. But I get redirected with the wp-admin

Okay, never mind my question. I deleted everything, did a new installation with a fresh export/import and everything seems to be working now.
the only difference was that my export now comes from the live site. The other one came from my local Ampps devsite.
Thanks for the replies!