I hope this helps.
Have you tried it on an iphone? It sounds to me like a problem with how your mobile phone is interpreting the link. If you try it on a different device, especially different operating system I feel like that would prove it pretty well.
If it doesn't work on iOS, it's probably a bug and you should let Tableau know by creating a support ticket.
I'd be happy to try this out if you publish a test to Tableau Online on my Samsung Galaxy. Another android test couldn't hurt.
Good suggestion but in this case I'm pretty sure we're dealing with a client side (mobile phone specifically) handing of an HTML mailto link, so the server side shouldn't be a factor.
Good point. It does sound like a client-side issue.
Thanks for reaching out and glad to see you leveraging the Tableau community for help. I don't have an android phone, so it'll be hard for me to test. What I do recommend is to test a couple of different scenarios to help pinpoint where the issue might be.
1. Try entering "mailto:firstname.lastname@example.org" directly into your Android web browser
2. Try hard coding your mailto in your URL dashboard action without the <Email> variable in Android
3. Test a normal URL action in Android with just a web address
4. Test the mailto action on a different type of phone, i.e. iPhone
If none of that helps or gives you more insight on the potential error, then you can try a simple hack. Send your user to a web page that will initiate the mailto function automatically.
Here's a link to help:
Hope this helps!