it was possible to connect autocad map and ArcGIS 10.2. After the upgrading to ArcGIS l0.3, It is not possible to connect with autocad map 3D-2015 according to Autodesk following links they were provided.
Its a 64 bit machine. PRODUCT DETAILS: Arcgis server Basic-10.3, Arcgis std desktop 10.3, and oracle 12 C DB.
I have tried all possible solutions for the above problem