i haven't checked on addy.io yet, but imagine it has something to simplelogin's alternative alias domains. i.e. aliases can be created from a choice of several domains.
most email rejecting sites/services have filters rejecting emails with:
- subdomains (@sub.doma.in instead of @doma.in) or
- rejecting known alias/temp email domains like @simplelogin.com or @guerrillamail.com for example.
try using other domains available from Addy. io
here we go again......
Viva C*****!