There's nowhere near enough information to judge with certainty. Do you have video or logs of the pull? The truth is most likely a combination of poor tanking and poor healing practices. The fact you needed to be told to use Holy and were spamming Cure II are massive indicators that you do not have a firm grasp on how to play WHM and makes me think it was most likely your fault more than the tank's.

A brief look at your lodestone page shows that you're wearing several i385 pieces. Not using full augmented Scaevan at level 73 definitely makes it harder to heal.

I assume you're asking for judgement because you legitimately wish to know whether you made a mistake and how to fix it. The game does a terrible job teaching new players how to make the most of their toolkits and it's very common for new healers to make big mistakes for multiple levels. Until a new healer is paired with a bad tank it's very difficult to wipe in this game so it's easy to believe that they're not doing anything wrong.

I would be happy to tank a couple dungeons for you and provide feedback. If you're interested you can reach me on Discord at Qina#4625.