What happened
The Verge reported on Nov. 8, 2019 that Syniverse, a company carriers use to route texts between networks, had released tens of thousands of messages that were stuck since Valentine's Day. Syniverse first said 168,149 messages were delayed, then said that number was based on 'preliminary data' and that the total 'is higher than initially reported.' It did not say how much higher or whether it would publish a final number.
Syniverse said a single server failed on Feb. 14, 2019, holding onto messages that had not been sent. The server was brought back online only on Nov. 7, which released the backlog. The Verge reported that in the US the messages were mostly delivered in the middle of the night, with nothing to show they had been delayed, so recipients were often confused. Some people received messages from exes, and in several cases the people involved had died since the messages were sent.
Because carriers rely on third parties like Syniverse to route texts between networks, people across all major carriers and some smaller ones were affected whenever either side's carrier used Syniverse. Syniverse's marketing and product chief, William Hurley, apologised and said the company was reviewing its processes to ensure this does not happen again.
Why it happened
One server failed on Feb. 14, 2019 and was not brought back online until Nov. 7, holding the messages for nine months.
Syniverse sits in the routing path between carriers, so a single failure reached customers of every major network.
The delayed messages carried nothing to show they were late, so recipients could not tell.
The lesson
A routing backbone where one failed server can hold traffic for nine months will hurt every carrier that depends on it. Delayed messages should be visibly flagged as late.
Aftermath
Syniverse said the issue was resolved and no more delayed messages were being sent. It said it was reviewing processes, and did not say how many messages were affected in total.
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