I am on holiday in Hungary. I can receive emails via thunderbird but not send them
My internet connection is good, When trying to send an emailE I get the message that it cant be sent.etreden bij het verzenden van e-mail. The mail server answers 5.7.1 Unable to relay this address
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Sometimes local ISP's may block port 25 which is commonly used to send mail. You could try your webmail to see if it works from there or check which port your outgoing server is using.
Thankyou, my outgoing port is 25. How do I know which other port number I can try?
What is email provider? We can then find out if they support other ports. Otherwise you could try port: 2525
Unfortunately 2525 doesn't work. My provider is kpn in the Netherlands
In Hungary I am not sure - I'll have to check and get back to you
It seems like they only support port 25. You could try sending through their webmail: https://webmail.kpnmail.nl/mail/logon.asp
This isn't a port problem.