This happens with v15 too.

The no "From" address thing has been a problem for a very long time (even SmarterTrack discards them), we're just now seeing problems with Gmail rejecting the emails.

Yeah this has been a problem for quite sometime for me as well. I am also on v15. The workaround for me, since I monitor this stuff, I just have it email me as a SMS message on my cellphone.

We can't get SMS forwards through either, and I'm assuming it's for the same reason. This really needs to be fixed. 

Almost a year later and this is still a major issue in v17.

I would have thought they would have addressed this issue in the latest version. I am still running v15 for the time being, so for me there's no more updates. You could try reaching out to support and see if this is on the Devs roadmap for future features.Other than that, you could post this in the suggested features section, but in order for them to consider it the community needs to up-vote it enough and even then it might be awhile.