Lsass Error 1225 (0x4C9) ERROR_CONNECTION_REFUSED – Unknown error

Hello,
I am getting this error, while trying to integrate my Ubuntu systems to windows domain:
Lsass Error
1225 (0x4C9) ERROR_CONNECTION_REFUSED – Unknown error
It's giving me too much headaches on how to get it working. Also, is this really possible? Has been trying to Google it and could not find anything that works. I'm still new to using Ubuntu systems, but I will do whatever it takes to fix this.
I am not really familiar with what I am doing, but this is the job that was assigned to me. I tried deleting lsass-adcache.db, but that didn't eliminate the error.
Any help is so much appreciated.
Thanks in advance.
