Can't get Pro features of WP Smush Pro - it keeps prompting me to upgrade to pro

I purchased WP Smush Pro and installed and activated it. My site thinks that I'm using the free version - it keeps showing me messages trying to get me to upgrade to Pro. Why is that?? I deleted the free version and it doesn't help.

I also see this message:
"Already upgraded to a WPMU DEV membership? Install and Login to our Dashboard plugin to enable Smush Pro features."
I have the WPMU Dev dashboard plugin installed and activated, but I do not see a link to it anywhere on the wp-admin sidebar menu - I looked very carefully, several times!

Thanks (in advance) for your help!
NS