Yes. The IMAP server address should be set to imap.merchantsecure.com
You can configure an SSL/TLS connection on port 993 or plain/STARTLS connection on port 143.
Please also double-check that the root folder path is set to /
As a reminder the SMTP server should be set to smtp.merchantsecure.com
The SSL/TLS connection is on port 2525 or you can use the plain/classic one on port 26 or 25.
You may also set up a POP connection instead of IMAP.
The POP host is pop.merchantsecure.com
You can configure an SSL/TLS connection on port 995 or STARTLS on port 110