Trouble with mail server sertificate

Trouble with mail server sertificate

FAILURE :E-mail settings saved successfully. Could not find valid certification path to requested target, so kindly configure to apply Trusted/Self Signed Certificate.

 I get this error, then  i configure mail server settings.Please help me!!!
Incoming port IMAPS 443,
Outgoing Port  SMTPS 25

                  New to ADSelfService Plus?