WP Smush Not Resizing/Reducing Upon Upload

Hello,

We just recently noticed for some reason WP Smush Pro will not reduce image size and optimize upon adding large images into the media library. We checked numerous times at the settings which are set to do so: http://jmp.sh/aCz2860

However, we can manually bulk and individual images. Is it possible that WP Smush Pro is not working properly because our wp-admin is under VPN? If so, is there IP ranges we could whitelist? We also have security policies for our websites (instances = RDS) and perhaps we might also need to whitelist inbound IP ranges there too.

If WP Smush Pro does not rely on any direct connection for file optimization upon upload, is there any other reasons it might not be working?

Thank you so much