E-Mails from 3CX are blocked as Spam because of sendgrid.net

[Severin Meyer]

When sending a welcome e-mail via the 3CX-SMTP-Server, the firewall is blocking the mail.
The firewall is blocking it because of the sendgrid.net link inside the mail.
sendgrid.net is listed in the spamlist https://admin.uribl.com/