Resolved
Email delivery has been restored now. Delivery of some of the previously sent emails (since yesterday) may be delayed.
Monitoring
We have deployed a fix and verifying the mail delivery
Identified
We are working in a solution for the Invoices-related mails not being sent (invoice payment, payment reminders, quote completions, etc).
This does NOT affect any other SumUp product - it affects only to SumUp Invoices.
Identified
We are aware of an issue sending some of the emails. We are investigating possible solutions for it.