Keep wiping at The Vault endboss with random parties

[Risvertasashi]

Well, people told me that about 2-3 other dungeons and trials before Vault - that they were a healer check - and I did just fine.

Being called a bad healer for failing one dungeon frequently is...well... or maybe I just feel I´m a bad healer.

Ok look. Here's a time honored and important healer mantra: You can't heal stupid. And vault punishes stupidity a lot.

It's good to seek to improve, but you can't shoulder responsibility for others' failures. But a tip to try to make up for it: If you get the chain on the last boss and the connected DPS doesn't move, just spam heals on yourself. The chain will break when the DPS dies, and then you can rez them and continue the fight. As a more general tip, just make sure to keep your camera positioned so you see the marches coming.

[Gavanri]

Ok look. Here's a time honored and important healer mantra: You can't heal stupid. And vault punishes stupidity a lot.

The thing is that I was clumsy as well. I think only the tank knew 100% what he was doing there (last man standing, always).
Anyway, will take the positioning advice to heart, thanks to everyone who posted^^