What login credential are you requested for solaris OS or for ILOM?
If it is OS, then you can put the auto-boot to false using the ILOM
If they are ILOM password and you don't remember it, this docs could help
How to reset the ILOM root password back to the default 'changeme' using ipmitool. (Doc ID 1328316.1)
How to Reset ILOM (2.0) Root Password on T5120/T5220/T5140/T5240 [Video] (Doc ID 1007050.1)