Oracle.ManagedDataAccess and ORA-01017: invalid username/password; logon denied

I have been struggling with this same issue for a couple of weeks and finally have a resolution. I had to disable the FIPS security policy, try setting this key: [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\FipsAlgorithmPolicy] “Enabled”=dword:00000000 to zero, it worked perfectly for me I was following your thread your blank password issue eventually pointed me here: https://community.oracle.com/thread/2557592?start=30&tstart=0