Does a sender address have to be an existing email address?

Yes, you must use an existing email address as the sender address.

Using an existing email address helps to prevent spam. It is not without reason that it is one of the rules drawn up by the Authority for Consumers and Markets (ACM) for sending newsletters.

Therefore, you cannot use a non-existent email address in Laposta. A confirmation mail is first sent to each new sender address. If this is not received, the sender address cannot be confirmed.

By the way, an existing email address is not only mandatory, but also very useful: it is good practice to give your subscribers the opportunity to respond to your newsletter.