Can't get Imap working over tls
on https no problems:
s_client -connect mydomain.com:https
CONNECTED(00000005) depth=2 O = Digital Signature Trust Co., CN = DST Root CA X3 verify return:1 depth=1 C = US, O = Let's Encrypt, CN = Let's Encrypt Authority X3 verify return:1 depth=0 CN = mydomain.com
Certificate chain 0 s:CN = mydomain.com i:C = US, O = Let's Encrypt, CN = Let's Encrypt Authority X3 1 s:C = US, O = Let's Encrypt, CN = Let's Encrypt Authority X3
on imap: openssl s_client -connect mydomain.com:imaps
CONNECTED(00000005) depth=0 CN = mydomain.com verify error:num=20:unable to get local issuer certificate verify return:1 depth=0 CN = mydomain.com verify error:num=21:unable to verify the first certificate
Certificate chain 0 s:CN = mydomain.com i:C = US, O = Let's Encrypt, CN = Let's Encrypt Authority X3
Derver debian 9 with 6 domains.