AppId is over the quota
13 October 2011 Last updated at 08:22 GMT Stephen Bates, RIM UK: "The back-up system did not operate in the way we would expect"Blackberry's owner RIM said that its services "have improved significantly", following a three-day global blackout.
Millions of customers worldwide had their messaging and email service disrupted with many turning to Twitter to express their anger.
RIM put the ongoing problems down to "backlog issues", following a system failure.
Users began to report loss of services mid-morning on 10 October and the problems spread around the world.
On Thursday, RIM issued a statement saying services across Europe, the Middle East, Africa and India "have improved significantly".
"We continue to monitor the situation 24x7 to ensure ongoing stability," the update on its website said.
The firm is keen to be seen as sorting the problems swiftly, following confusion earlier in the week when it said services were back to normal, only to be contradicted by frustrated customers.
Robin Bienfait, chief information officer of RIM, the Canada-based owner of Blackberry, issued an apology for the ongoing issues.
"You've depended on us for reliable, real-time communications, and right now we're letting you down. We are taking this very seriously and have people around the world working around the clock to address this situation," he said.
"We believe we understand why this happened and we are working to restore normal service levels in all markets as quickly as we can."
It blamed the ongoing issues on a backlog of emails to Europe from Asia and the Americas, following a "core switch failure" in its infrastructure.
"Clearly we have a backlog in Europe... as you can imagine, with the global reach of Blackberry and people using it to contact others around the world, there's a lot of messages to Europe from Asia and the Americas," RIM software vice president David Yach told a press conference in Ottawa, Canada.
"Over time that backlog has built up and affected our other systems."
'Data backlog'
Many tweeters called on the phone firm to "sort out" the problems and get the network running again.
RIM eventually explained what had caused the problems in the first place.
"The messaging and browsing delays... in Europe, the Middle East, Africa, India, Brazil, Chile and Argentina were caused by a core switch failure within RIM's infrastructure," a company statement said.
"Although the system is designed to failover to a back-up switch, the failover did not function as previously tested.
"As a result, a large backlog of data was generated and we are now working to clear that backlog and restore normal service as quickly as possible."
The server problems are believed to have originated at RIM's UK data centre in Slough.
The "issues" left many Blackberry owners only able to text and make calls.
BBC's Rory Cellan-Jones: "Blackberry has so many high profile users who are complaining about the crash"Such a major failure will come as unwelcome news to RIM, which has been losing market share to smartphone rivals - in particular Apple's iPhone.
Many corporate clients have switched to the device after Apple made a concerted effort to improve its support for secure business email systems.
Malik Saadi, principal analyst at Informa Telecoms & Media, said the timing of the outages was bad for RIM.
"The current situation with the Blackberry outages couldn't come at a worse time for RIM, following some harsh criticism in recent months," he said.
Such crashes may lead RIM and others to "re-evaluate their reliance on centralised servers and instead look to investing in more corporately controlled servers", he added.
But he thinks customers will stick with the firm despite current frustrations.
"It will take more than just a couple of collapses to persuade loyal consumers of Blackberry services to look for alternatives," he said.
