East Sussex Fire and Rescue Service said it was called at 18:39 BST and two fire engines were sent to the scene to assist.
The i360 pod was carrying a private party, including a heavily pregnant woman, who boarded the pod at about 17:00.
It was lowered to the ground about two hours later.
The BAi360 Twitter account said: "Our engineers are resolving the problem & expect it to be working normally soon."
A local firm of building and quantity surveyors, MacConvilles, tweeted saying: "Our Director is enjoying the hospitality of the #i360. Technical hitch has halted ride but help is on its way!"
Tim Jones, one of the party organisers, said: "We weren't very high up when we juddered to a halt and we were told by staff to move to one side of the pod to 'recalibrate the weight' - which made some people a bit nervous.
"It was an interesting experience, and quite ironic as the party was organised by four local businesses who wanted to come together to celebrate the tower's opening."
"Only two interactions were made over the two hours and they kept pretty quiet about the free bar and the emergency toilet until we were nearly on the ground," he added.

Members of the armed services accompanied the hearse as it arrived at the library in the Simi Valley city.
The funeral takes place on Friday.
Nancy Reagan died at the age of 94 last Sunday. Her 52-year marriage to Ronald Reagan was once described as the US presidency's greatest love affair.
Mrs Reagan, who died of congestive heart failure in Los Angeles, was praised by President Barack Obama's family and other senior US politicians and foreign leaders.
From 1981-89 she was one of the most influential first ladies in US history, initially criticised for an expensive renovation of the White House, but later becoming a much-loved figure.
Nancy Reagan: Her husband's greatest supporter
Praise for 'devoted' First Lady
Mrs Reagan will be buried next to her husband at the presidential library.
Like her husband, Mrs Reagan was a former Hollywood performer who made it all the way to the White House.
As Nancy Davis, she was an actress during the 1940s and 1950s and married Mr Reagan, a prominent film actor, in 1952.
She served as first lady of California during her husband's stint as California governor from 1967 to 1975 before moving into the White House after his decisive victory over Democrat President Jimmy Carter in 1980.
As first lady, she sought to emulate the style of one of her predecessors, Jackie Kennedy.
To this end, she extensively redecorated the White House, and accepted designer dresses worth $1m (Â£703,000) and a 4,732-piece set of china worth $209,000.
But this spending spree provoked an outcry from some outraged by what they saw as profligacy and waste while millions of Americans were losing their jobs.
Public opinion was also swayed by accusations that Mrs Reagan had a frosty personality, often consulted astrologers, and ordered the dismissal of White House chief of staff Donald Regan in 1987.
"I see the first lady as another means to keep a president from becoming isolated," she once said.
Mrs Reagan's best-known project as first lady was the anti-drugs "Just Say No" campaign.
After her husband died of Alzheimer's disease in 2004, she became a champion for Alzheimer's patients, raising millions of dollars for research and breaking with fellow conservative Republicans to argue for stem cell research.
A "technical hitch" has been blamed for leaving 180 passengers stuck on British Airways's i360 attraction in Brighton.
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The coffin of former US First Lady Nancy Reagan has been placed in the Ronald Reagan Presidential Library in California for public viewing.