If sending e-mails to e-mail addresses in a specific domain (for instance gmail.com or bluewin.ch) fails

When e-mails are sent to recipients on certain domains (e.g. gmail.com, bluewin.ch, etc.), they may be rejected by these domains as being suspicious.

In order to prevent the phenomenon of spam (advertising e-mails sent en masse), various techniques have been put in place to distinguish legitimate senders from spammers. Among the techniques used are SPF and DKIM, designed to verify the authenticity of the sender.

Gmail explains how to configure the DNS server so that the sender's domain name is considered reliable. Please note that this configuration must be carried out by an IT specialist responsible for administering your domain name. Contact your e-mail hosting provider for more information.