Humming Bird / GZIP Compression (Deflate function)


Im currently operating a WP site on Google Cloud's Compute Engine. According to Hummingbird's Gzip Compression feature it is saying that compression is not working well and that Deflate may not be enabled.

What can be done to address the issue?
Is there anything I can check to ensure that the feature is there and running on the server?
Please advise.