Alex, et al.,
I spoke too soon. Upon close examination of /var/log/maillog, the errors previously reported via the maillog extracts only happen when I attempt to test the imap connection. Everything appears correctly set up, defined, etc. It's now down to the certificates themselves I think. I have the following files:
. A file containing the certificate as issued by the certifying uthority that sold it to me. This file has a .CRT extension.
. The certifying authority's standard (or intermediate) certificate. This file has a .PEM extension.
. The private key file I generated when I created the CSR which was submitted to the certifying authority to create the signed certificate for my domain. This file has a .KEY extension.
I created the certificate file by opening a new text buffer in the editor of my choice and reading in the first and second of the above three files, then saving the concatenated buffer as /etc/pki/dovecot/certs/tgv2015.crt