[Hummingbird Pro] GZIP compression not working

I have had gzip compression enabled on my site before. when I disabled Hummingbird then reenabled it it stopped working giving me this error:
Gzip is not working properly:

Your server may not have the “deflate” module enabled (mod_deflate for Apache, ngx_http_gzip_module for NGINX). Contact your host. If deflate is enabled, ask why all .htaccess or nginx.conf compression rules are not being applied. If re-checking and restarting does not resolve, please check with your host or open a support ticket.

Please advise