What does it mean one ring and straight to voice mail?

So I've been friends with this person for a while I tried calling her twice today no answer. Doesn't answer my texts and I can't tell if I'm blocked because I'm on iPhone and she s on droid. Should I text her if I've been blocked?

Phone off or blocked.

She's either ignoring the calls or have you blocked or she has phone on do not disturb or letting voicemail pick up call after one ring