(the 2019 break was caused by a Turkish oil tanker prematurely dropping anchor in a restricted zone [3])
"DS Venture Ltd (DSV) was the owner of the Duzgit Venture. On 20 January 2019, as the vessel approached the Port of Nuku'alofa, its starboard anchor and chain were prematurely released from their housing. As the anchor and chain were winched back in, they caught and damaged a cable. The cable was one of two undersea communications cables owned by Tonga Cable Ltd (TCL) connecting Nuku'alofa, Ha'apai, and Vava'u with Fiji. As a result of damage to the cable, Tonga was without cable telecommunications for almost three weeks. "
[0] https://samoanews.com/regional/tonga-cable-break-located-rep...
[2] https://matangitonga.to/2019/01/26/geek-heroes-rescue-tonga-...