Telekom Malaysia Berhad recently made an annoucement, TM will block OUTBOUND Simple Mail Transfer Protocol (SMTP) traffic or port 25 for all out going e-mails from dynamic IP addresses. Only Outbound SMTP traffic from his proxy will be allowed. You may change your smtp to port 26 as Nocser run alternative smtp port 26.
With this implementation, Streamyx or TM customers, must make some changes on your Email client. E-Mail will not be able to send without this change. Please follow instruction below to make this change http://webmail.tm.net.my/info/proxy.html