yes, it’s probably hardware, or erhaps the taret TRX is using a frequency that is interfered. So the MS cannot access this particular TRX.
Normally HO failure is also linked to the CSSR. In both case, the MS tries to access a TRX.
If HO failure, then there should be also a low CSSR.
Is it your case ?
If not then you must suspect a problem linked to HO only (wrong parameters ?)