theme stoping me getting into dashboard

my site is relieve-the-pain.com

What happens when you go to https://relieve-the-pain.com/wp-login.php?

From my end: https://relieve-the-pain.com/wp-login.php?redirect_to=http%3A%2F%2Frelieve-the-pain.com%2Fwp-admin%2F&reauth=1 is working fine.

Can you check the theme’s functions.php file in line 1500 in a text editor and get the code for us?

Your theme may no longer work with your version of WP – to test, rename the theme’s folder to old-theme_folder_name, making sure to have an unedited version of the default theme in place first.

WP will then default to the default theme.