Troubleshoot WP login loop issue

3 page static WP site was transferred from BlueHost to GCP. The site’s active, but WP login loops to home landing page after entering credentials. Disabling (phpMyAdmin ) template theme and plugins did-not provide WP login access.

Corrupt file, or missing file?
- WP login credentials are correct
- WP login pw reminder is-not sending email to reset pw
- website Contact form produces an error

Your help trouble-shooting would be appreciated.

Thank you