Oracle Error 12560 generating big sqlnet.log file

I have a Windows 2008 server which have two versions of Oracle: 11.2.0 and 12.1.0

A huge log file is being generated on the following path:

C:UserstheUserOracleoradiag_theUserdiagclientsuser_theUserhost_3095494057_80tracesqlnet.log

This file is being written every second with the following error log:

            Fatal NI connect error 12560, connecting to:
             (DESCRIPTION=(ADDRESS=(PROTOCOL=BEQ)(PROGRAM=oracle)(ARGV0=oracleORCL)(ARGS='(DESCRIPTION=(LOCAL=YES)(ADDRESS=(PROTOCOL=beq)))'))(CONNECT_DATA=(SID=ORCL)(CID=(PROGRAM=G:applicationapplication_process.exe)(HOST=server_name)(USER=user_name)))

              VERSION INFORMATION:
                TNS for 64-bit Windows: Version 12.1.0.1.0 - Production
                Oracle Bequeath NT Protocol Adapter for 64-bit Windows: Version 12.1.0.1.0 - Production
                Windows NT TCP/IP NT Protocol Adapter for 64-bit Windows: Version 12.1.0.1.0 - Production
              Time: 18-MAR-2016 13:06:35
              Tracing not turned on.
              Tns error struct:
                ns main err code: 12560

            TNS-12560: TNS:protocol adapter error
                ns secondary err code: 0
                nt main err code: 530

            TNS-00530: Protocol adapter error
                nt secondary err code: 126
                nt OS err code: 0

So at that point the file get so big that my server run out of space. I’m trying to determine why this happens, I have been investigating a lot and I suspect that is an ORACLE_HOME issue, but still can’t prove this.

Someone experienced something like this before?