"Invalid Email" error when trying to "Share with my doctor"

When I click on a blood pressure reading, click the "..." in the top right corner and select "Share with my Doctor" I get a screen where I can enter a recipient. I enter a valid email address and select any of the options for the "Extended" option then click "confirm". I get a pop up error "Invalid Email address". I have tried a few different email addresses and it doesn't seem to matter. My email address on my Withings account is verified and valid, so I'm not sure what the problem is. I share my blood pressures with my doctor weekly and since getting my new BPM connect for Christmas, I've not been able to export out my blood pressures without doing the large data dump, which is total overkill for just 1 week's worth of blood pressures.

I have also tried killing the Health Mate app and rebooting my phone

I appreciate any help