unbox.at seems greylisted since emails are received with a delay
Emails received through unbox.at have a delay that goes from 5 minutes to 1 hour.
This behaviour seems equivalent to greylisting and have a huge impact on email verification processes or OTPs, since they are time based, rendering unbox.at unusable with murena.
unbox.at is an addy.io instance that provides anonymous email forwarding. Basically, instead of giving your real email address you can create an alias for every service and use it; so in case of spam you can just delete and replace that alias, plus you know who messed up with your data.
Till now, I never received spam through unbox.at. Nevertheless, even in case few aliases starts receiving spam, the entire service unbox.at should not be affected by murena in this way.
PS: I already contacted the murena teams months ago and provided some eml, but nothing is changed.