There is a possibility that the server is down. I was not able to connect to that server
either. Have you called their tech support?
The only other possibility is a port 25 block. When you got that error
message was your Internet connection being obtained from Concepts.nl?
If not, what you experienced is normal. As a general rule, the owner of
the SMTP server you are using must be the same as the entity providing
your Internet connection at that moment.
Let us know the circumstances (sending from home or away from home),
and we can provide some workarounds.
Gary VanderMolen, Microsoft MVP (Mail)
Als we mail proberen te ontvangen met Windows Mail krijgen we sinds gisteren
de volgende melding:
Het verbinding maken met de server is mislukt. Onderwerp 'test', Account:
'pop3.concepts.nl', Server: 'smtp.concepts.nl', Protocol: SMTP, Poort: 25,
Beveiligd(SSL): Nee, Socket-fout: 10013, Foutnummer: 0x800CCC0E
Hoe is dit op te lossen?