Follow I can't log in to RETS via Internet Explorer or Firefox. Why? February 11, 2016 21:14 MLS Technology Inc. Knowledge Base RETS / IDX Our RETS server only supports the use of a RETS Client Application - You can visit the Center for REALTOR Technology’s site for information on Client Applications (and there are also additional resources available beyond the specified sites). 0 Comments Article is closed for comments.