having issues transferring from WINSCP to Wingftp

Is there A setting or something that I am missing. When I try to connect to my WingFTP server from another server that is using WINSCP it works for one day and then the next day I get this message. I not sure where to go from here. Below is a screen shot of the prompt that I am receiving in WINSCP.

Please contact the server administrator. In general this should not happen. But we cannot know if your server really changes host key every day (should not). Or if it is another problem (MITM attack, load balancer, ...)