Conversion of Excel file to pdf getting error

Question

I am Converting Excel file (i.e 2003,2007,2010 and office 365) to pdf but i am geetting error like (System.Runtime.InteropServices.COMException (0x800A03EC): Exception from HRESULT: 0x800A03EC) or (Exception from HRESULT: 0x800A03EC) on windows server2012 R2. Docx , doc , pptx,ppt file successfully converted into pdf and i have install office 365 on the server (i.e windows server 2012 R2). Pleas help me out. i am getting stuck from last 4 to 5 days.