Can send emails but not receiving to outlook

Can send emails but not receiving to outlook

Out domain name is tjay.lk our mails can be sent via outlook but its not receiving. can you please check it as soon as possible? getting an error message : log onto incoming mail server (POP 3): Outlook connect to your incoming (POP3) e-mail server. If you continue to receive this message, contact your server administrator or Internet Service Provider (ISP) 

thanks
buddhika