Other emails seem to be working, but I haven't gone through all of them as yet. Sorry, I made a mistake in my original post - one is AMPPS (testing and development) and the other is on a server which is hosted by a company in Serbia. osTicket Version - v.1.9.11 (c1b5a33)web server - Apache/2.2.29 (Unix) mod_ssl/2.2.29 OpenSSL/1.0.1e-fips mod_jk/1.2.37 mod_bwlimited/1.4 PHP - 5.4.38Using IMAP for emails I believe phpMail function for sending mails too. Thank you for your help