Database link from Local Oracle 11g to Oracle Database Cloud Service 11g
That is not how you connect to another database through database links. Database links require SQL*Net connectivity, not HTTP(S).

First you need to enable access, then you can connect using the address of the compute node and the service name for your database.

http://docs.oracle.com/cloud/latest/dbcs_dbaas/CSDBI/GUID-372D4233-9793-47EC-8DFC-AFD6CF32866C.htm#CSDBI3449