After updating to user_restrictions-7.x-1.0 in drupal7, I can no longer run cron from another host I've been updating several drupal7 installations from one browser on the same host as ONE of them.  I just did this, updating to user_restrictions-7.x-1.0 on both machines.  This caused no problems on the host where my browser was running, but on the other host drupal will no longer run cron manually at my request, and clicking on the "To run cron from outside the site, go to http:///drupal/cron.php?cron_key=..." link yields an "Access Denied" message.  

Under the circumstances, I must conclude that something significant has changed in user_restrictions-7.x-1.0 that enforces some exclusion on the basis of IP address that didn't exist before or was not previously being enforced.  

How do I grant my other host permission to use the cron_key in question?
The User restrictions module just restricts which users can log in basing on their username and email address; if the username or the email address matches a regular expression set in the module settings, the user is not allowed to log in. At the same time, the module doesn't allow users to change their usernames or email addresses to values that match those regular expressions.

The modules doesn't restrict user access basing on their IP, since that functionality is still present in Drupal 7 core, although Drupal core just allows you to set an IP address, not a range of IPs to ban.
If you are experiencing what you reported, then it could a module bug. Report it in the project queue, once you verified there isn't a issue already opened for that, and that the module is really the responsible for that behavior.

Disclaimer

I am the maintainer of the module, although I didn't change the module code recently. I don't plan to develop any Drupal 7 module, since I am focusing on Drupal 8 development.