wp-admin white page and wp-login.php doesn’t work

I use3d Duplicator to setup a development site for testing purposes. The new site works perfectly, identical to the original, except wp-admin is a white page. Access to wp-login.php directly works, but doesn’t login. I found several articles in white pages for WP, but I do not get white pages everywhere, the site is working well. I found a few topics similar to my problem, so I tried their suggestions.

So far I have :

– deactivated all plugins in phpMyAdmin (didn’t work)
– changed theme to default theme (didn’t work)
– renamed the plugins folder in cPanel to have WP deactivate the plugins itself (didn’t work)
– renamed the .htaccess file to pretend it is not there (didn’t work)
– tried copying the content of the original .htaccess file into the new one (didn’t work)
– tried reinstalling entirely in case something went wrong on install (didn’t work)

When I click on “Forgot password” and enter a user name or email address, I receive the email with associated username and email combination. So the information is in the database. But when I click on the change password link, nothing happens, I get a white page.

I have opened a similar ticket with my theme vendor in case it is theme related, but could you help me from a plugin standpoint?

Thanks in advance for any help or new hints!

Marc

The page I need help with: [log in to see the link]