Steps to configure SSL encrypted http destination

Steps to configure an SSL-activated http destination in ABAP for an
external server:
+,,Create http destination in ABAP system. Enter the host and port of
External Server. In the "Logon & Security" tab, activate SSL and choose
?DFAULT SSL Client (Standard)?.
+,,Download server certificate of external server.
+,,Import this SSL certificate into the ABAP system in transaction
STRUST. Upload certificate at ?SSL client SSL Client (Standard)?.
+,,Connection test for the newly created http destination must be
successful now.

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.