Komatsu D37E-5 won't move

Machine was running fine, started it the next morning and let it warm up, went to move the machine and nothing, won't go forward or backward.

All oil levels are good. Checked for pressure up to joystick and there is none.

Any suggestions? Seems like it is likely something simple since it WAS just working fine. No slipping, no issues.

Komatsu D37E-5 won't move