poll imap.mydomain.tld with protocol IMAP user "myuser" password "mypassword" is "mylocalunixuser" here ssl sslfingerprint "5A:16:55:1D:61:1A:B3:B0:84:6C:04:8E:E6:15:A5:82" sslcertck sslcertpath /usr/local/homegrown/maildock/.certs
For the sslfingerprint type
fetchmail -v imap.mydomain.tld
and get the fingerprint.
For the cert type
openssl s_client -connect imap.mydomain.tld:993
get the cert and put it into a imapcert.pem file. Put that file into a .certs folder. Then rehash it with
mylocalunixuser should be a member of the mail unix group