Until recently I believed there was no solution to fix this issue besides waiting for the nether to reset again starting at the beginning of the month. However, there is a way to fix your nether portal! Typically, when your portal does not let you teleport to the nether it means that the location is not safe to spawn in. By using this site and the coordinates of your island you will be able to track down your nether portal and essentially make it safe! Nether Portal Calculator - Login Link Finder (nethercraft.net) For example, the overworld coordinates of the nether portal I recently fixed was located at -50008 203 27804 - you can use F3 to locate your island coordinates [make sure it's facing your nether portal] The website will then turn the coordinates in which the nether portal should have spawned in, those being -6251 203 3476 - by traveling here you'll be able to find the nether portal and free it from its enclosed location. Although it's a hassle to travel this far to locate it, it provides a way to fix your portal if this issue ever occurs. Thanks for reading!