Cannot Update Founder Pro

When I try to update the FounderPro plugin, from 1.19 to 1.21, I get the following message “An error occurred while updating Founder Pro: Update package not available.” Furthermore, on the WP update page, when I click “View Version 1.21 details,” the first time a popup shows with the details. But if I click again, I get another error message in the popup, “An unexpected error occurred. Something may be wrong with www.remarpro.com or this server’s configuration. If you continue to have problems, please try the support forums.”