Phenomenal demand for the sold-out Harry Potter And The Cursed Child play has seen booking extended until January 2017.
Fans scrambled for tickets when priority booking for performances from June 7 to September 18 2016 opened at 11am on Wednesday morning but seats sold out quickly.
Demand for tickets led to technical difficulties with the online system, including the site freezing and locking customers out of their purchases, which meant many disappointed fans who had waited up to three hours in the queue could not complete their transactions.
Producers have now put on sale a second booking period, running until January 8 2017.
Max Engel tweeted: "After waking up early and waiting for hours, #CursedChild had a broken site and sold out. Very disappointed."
Amy Blackwell wrote that she had missed out on tickets because of a technical problem with the pay system: "Can't buy tickets for @HPPlayLDN even after waiting 2+ hours & have them in my basket. No pay button!!"
Cheaper priced tickets sold out within the first hour, leaving younger fans unable to afford the £130 price tag for top tier seats.
One Twitter user wrote, "Unfortunately, by the time I got through only tickets at £130/each available. I could not afford £260 so missed out."
Third part re-sales site were offering tickets hours after the booking opened, with prices reaching up to £2,950 for both parts.
The play's official Twitter account warned people not to resell tickets, posting: "If you can't use your purchased ticket, please refer to the play website which gives details on refunding your ticket. Please do not attempt to resell your tickets on alternative platforms, as patrons will not be admitted into the theatre."
Fans have criticised those taking advantage of the ticket sell-out. One Twitter user wrote: "May all the touts reselling #CursedChild tickets be cursed to forevermore burp slugs."
JK Rowling announced through her website Pottermore last week that the plays would be a sequel to the books, taking place 19 years after the events of The Deathly Hallows and focusing on a grown-up Harry and his middle child Albus Severus.
The hotly-anticipated play is based on an original story by Rowling, written by Jack Thorne and directed by Olivier-winner John Tiffany.
It will receive its premiere at the Palace Theatre in London's West End next summer, with the two parts designed to be viewed on one day or on two consecutive evenings.
Previews will begin June 7 2016 with the opening performances on July 30 2016. In addition, four special preview performances are planned for the end of May 2016.
For those who miss out, there will be a weekly release online of 20 tickets for each performance every Friday at 1pm and a day ticket lottery with a further 20 seats released for the duration of its run.
Tickets go on general sale on Friday October 30 at 11am.