Another fan tweeted that they needed to sort out the sound issues.
Fans in the stands were particularly affected, with complaints that they could not hear what the stars were saying.
But others tweeted praise. One wrote: “Reliving the childhood was amazing, felt so emotional.
“Best night ever #SpiceWorldTour2019 #GirlPower #wannadoitagain.”
Spice Girls star Melanie Brown – otherwise known as Mel B – thanked their fans for attending the Dublin show in a video message on her Instagram story.
“We will see you in Cardiff. And hopefully the vocals and the sound will be much, much better, pfft,” she said.
Brown, Geri Horner, Emma Bunton and Melanie Chisholm performed the 1990s group’s biggest hits in a dazzling show which included a number of outfit changes and messages of diversity and unity throughout.
The show kicked off with Baby, Scary, Ginger and Sporty taking to the stage in extravagant fashion for their first number, wearing hand-embellished Swarovski crystal costumes designed by Gabriella Slade.
They opened the show with the message: “We welcome all ages, all races, all gender identities, all countries of origin, all sexual orientations, all religions and beliefs, all abilities.”
Horner greeted the crowd saying: “Welcome to Spice World. Spice girls, spice boys, everyone is welcome. We want every single one of you to feel special tonight. Like a king or a queen, we celebrate you. But I got to say there are a lot of queens here tonight.”
Chisholm told the crowd it was very special for the band to be back in Dublin.
She said: “In ’98, we started our world tour in Dublin, so we truly are home. It’s got a very special place in our hearts.”
During the show, they performed a number of their hits including Who Do You Think You Are?, Viva Forever, Wannabe, 2 Become 1, Say You’ll Be There, Mama and Stop.
The stage, which featured an imposing Spice World sculpture and large screens on each side, was used to display messages of female empowerment, including “We are stronger together” and their motto “Girl Power”.
It is the first time the group has performed since the closing ceremony of the London Olympics in 2012.
The group is undertaking the 13-date tour without original Spice Girls member Victoria Beckham, who has decided not to join them.
The band had to deny rumours of a rift in April following Brown’s claims that she had a one-night stand with Horner in the Spice Girls’ heyday.
But on the opening night, there did not appear to be any tension between them. They laughed and joked with each other throughout the show.
The Spice Girls will now head to Cardiff, then Manchester, Coventry, Sunderland, Edinburgh and Bristol. They finish their tour at London’s Wembley Stadium.