Hummingbird slows down the site

Hummingbird is causing this server error:

[Wed Feb 21 22:46:24.664630 2018] [:error] [pid 20143] [client] PHP Warning: file_get_contents(https://hb-minify-ju…2c7-4d4c-b419-d6d3da8cd73f.css): failed to open stream: Connection timed out in /path/to/wp-content/plugins/wp-hummingbird/core/modules/minify/class-minify-group.php on line 1197

According to hosting provider, the error is caused when the plugin is getting cut off by their long process kill script. They said that the kill script only runs if it’s been over 60-120 seconds and the process hasn’t completed.