The Made In Chelsea star's elder brother Michael died in 1999 aged just 22 whilst climbing Mount Everest and the reality TV star's film of his own expedition to bring back his late brother's body was due to air on the streaming service on Friday 3 March.
Matthews, 34, said in a statement: "Apologies to everyone trying to view Finding Michael on Disney+. The debut date has shifted and we'll update you as soon as we have the timings.
"This will be in the near future. Thank you all for your support."
Watch: Spencer Matthews claimed Everest to search for his late brother's body
Disney+ added: "We’re sorry that the debut date for Finding Michael has shifted on Disney+. We will let you know as soon as we have new timings for its launch. This will be in the near future. Thanks for your patience."
No explanation for the delay has been given.
Many disappointed fans expressed their frustration on social media.
Another said: "@DisneyPlus have really messed up with #FindingMichael Pretty poor customer service with virtually no communication made about delay of documentary that so many of us were looking forward to. Feeling sorry for Spencer and his family too."
One subscriber claimed a customer service advisor had told her the documentary was being re-edited at the last minute.
She wrote on Twitter: "#FindingMichael - talking to the lovely lady on Customer Service at Disney Customer Service and she has informed me that it was pulled for important re-editing. So the producers took it back."
Matthews journeyed to Everest last year on an expedition to make the emotional film about his family's grief for his elder brother.
He said previously: "It was important for me to get my head around the fact I might come face to face with my brother’s frozen body.
"I knew it was going to be a gut-wrenching and emotional journey."
Matthews said: "I'm not a particularly externally emotional person. I cant really remember the last time I cried."
But he added: "It was certainly one of the greatest experiences of my life."
The reality TV star said his wife Vogue Williams was very supportive of his decision to journey to Base Camp in Nepal for five weeks when their son Otto was just five days old.
The couple married in 2018 and are parents to four-year-old son Theodore, two-year-old daughter Gigi and 11-month-old son Otto.