What causes the issue
Likely what is occurring is the server is blocking the request. To correct this you will want to get in contact with your server host (WP Engine users can contact support over live chat for a quick resolution).
How to fix the issue
Step 1: Contact your server host and provide them the following information
1. That you are working to install a plugin and a request to ambitionallyaccess is getting a 403 error
2. Request they verify this in the access logs to verify the error
3. Inform the server host that ambitionallyaccess is an update server and the plugin will need to ping it for updates
4. Ask that the user-agent be whitelisted and that the IP address is not being blocked
Your server host should be able to confirm these and ensure they are whitelisted. Please verify at the end and then re-test your plugin installation. This should then remove the error.
Once you’ve contacted your server host and followed the above steps, attempt to install your plugin again. You shouldn’t see the error this time and should be able to install it.
Pro-Tip: Try to reinstall while you’re still connected to your server host, that way if there are further issues, they’ll be able to troubleshoot with you right away.