Welcome
Error sending email: Sending email failed: 5.7.1 Service unavailable; Client host [192.168.15.49] blocked using zen.spamhaus.org; Error: open resolver; https://check.spamhaus.org/returnc/pub/172.71.181.5/
This example sends an email on the backend using the FHICT mailserver which everyone from FHICT can use: mailrelay.fhict.local
It uses NuGet package: NETCore.MailKit
Full source and instructions can be found at https://git.fhict.nl/I872272/sendemailonbackend