Why don't you make a boolean property which if is true you can walk through the block and setting the boolean property to true for the blocks the player is looking at and if the entity (in this case the player) matches the condition i would do it like this it's not even hard to code
You won't get any support since 1.12.x is not supported any more on this forum you need to use a higher version of minecraft 1.14.x - 1.16.1
Note: If anyone would help you they would need your debug.log log and not this one
It's probably because this mod called Night Config is not compatible with this forge version most likely something changed in the forge code and that mod is use some stuff which changed so don't use that mod and it should run if this is the only error you got.
Sorry i didn't see your pic i only read the first and last comment to see if you was able to solve this issue. I usually setup a new directory rather than using the Example one that's why i said to just delete it.
It's me sorry i misunderstood what you said also i told you posted this in the modder support section sorry (i was also confused because i didn't understand why anyone would make a nether portal if it's already exists xd)