Error: “The page isn’t redirecting properly”

I’ve restricted a page to certain roles.

When the public visit that page, they are prompted to login @

After they login, they are redirected to:
https://staging.orsgroup.com.au/eapportal/wp-login.php?redirect_to=https%3A%2F%2Fstaging.orsgroup.com.au%2Feapportal%2Fcontent%2F&error=mkdo-rcbr-no-access

where they receive the error:

The page isn’t redirecting properly

Firefox has detected that the server is redirecting the request for this address in a way that will never complete.

This problem can sometimes be caused by disabling or refusing to accept cookies.

Here are my WordPress .htaccess rules (it is a MU site):

# BEGIN WordPress
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
# uploaded files
RewriteRule ^([_0-9a-zA-Z-]+/)?files/(.+) wp-includes/ms-files.php?file=$2 [L]
# add a trailing slash to /wp-admin
RewriteRule ^([_0-9a-zA-Z-]+/)?wp-admin$ $1wp-admin/ [R=301,L]
RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?(wp-(content|admin|includes).*) $2 [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?(.*\.php)$ $2 [L]
RewriteRule . index.php [L]
# END WordPress

Help appreciated.