Tell us what you are trying to do?
Download Access (Toolset already registered) but get the message Download failed. (Forbidden) on production (works fine in development)
Is there any documentation that you are following?
No
Can you check the custom installer debug page to see if there are any issues reported?
Go to Toolset > Settings and follow the debug link at the bottom, then follow the Installer Support link at the bottom (or access the page directly at site.com/wp-admin/admin.php?page=otgs-installer-support).
You can try installing Access by downloading the zip file of the latest version from toolset.com/account/downloads and then from the Add New Plugin page upload the zip file.