It has come to our attention that some users who are with HostGator are having issues installing Extensions. It has been reported that they receive a 403 error page. We have looked into this and discovered it is a problem with HostGator’s server configuration. They are blocking remote file downloads that originate from Amazon S3, which is where we host all of our products. X relies on the TGMPA library for our extensions system, and there have been reports from other users as well which you can see here. We’re looking into any solutions that are possible from our side. If you’re experiencing this, you may wish to contact HostGator to see if they can lift the restriction for you. Additionally, all Extensions are included in the All files & documentation download from ThemeForest and can be installed manually if desired, or if a situation like this arises; however, automatic updates will not work for situations like this since it is due to a server configuration.

I hit exact same issue few days ago, and followed advise given here, asked them to lift restrictions and they did!

so, to make story short, point their support to this forum thread and ask them to check the mod security rules if any are being hit.

Thank you for sharing your experience. Yup, asking the HostGator to lift restrictions would do.

Thanks.

For hostgator users, yes it is still going on.

One known solution is contacting HostGator support chat and making this request:
“Please whitelist rule ID 1234234″

Thanks