Sudden problems when despatching e-mails have occurring for a while now. Instead of the e-mail being despatched, the attempt is recorded with an error report (e.g. socket error 10060 error number 0X800C...). This only happens when e-mail programs are used (Outlook and Co). The despatch of e-mails through a browser (IE, Firefox and Co.) and a web interface is not affected. The cause of the problems is usually that the internet service provider (ISP) has blocked port 25 for the customer. The provider wants to counteract the increasing number of spam e-mails with these measures.
Change the settings of your e-mail program (Outlook Express example)