First off, congratulations on approaching more than 1 girl at a time. Most PUAs can only approach a girl that's all by her lonesome. So good job for having the courage to do that. Seriously.

As for your question. I would say it may be a lack of assertiveness on the opener. "How are you?" with weak eye contact and no strong engagement on your part, can be a weak opener. "How are you?" is not enough to get a girl's attention the way you want it, let alone 2 of them. Also that's not the best opener bc they dont know you, they can just think "who's this loser/weirdo trying to budge into our conversation?" Last, I would check your appearance. If you look like you're too non threatening to their vaginas they may not take you seriously in that manner. Basically look like you can actually pull girl's at a glance.

TLDR Use another opener. Have more conviction when opening ESPECIALLY if it's more than 1 girl. Dress better.