I cannot use /NTP or a vanilla portal to travel to the nether. I can give a list of mods, or send my mod pack if needed - it is custom, quite light.

NTP command throws an error (am OP'd), Portal does light, but standing inside gives the usual effect but does not teleport to dimension.

Sorry I can't provide more information right now, I'm not sure what is useful to you.

Are you sure it's Infernal Expansion causing this? If you could send a log that would be great too. Put the files in the logs folder in a pastebin (I recommend paste.gg) and reply with the paste link.
If you could also provide a modlist, and some information about the system you're running on (32 or 64-bit, ram and processor, os), that would be helpful.

Naturally, no I'm not certain - but it's the biggest portion of code which will affect the way the nether works, so I'm here first. But I suppose it could also be another Dim mod, too.

I will be disabling mods and repackaging everything to see if I can narrow it down, if i get time this weekend.

64-bit Win 10, on Ryzen 3600X, 32GB ram, 1070 TI. Shouldn't really have any influence on the issue, surely?

https://paste.gg/p/anonymous/49e0528c2ff7473185c89d5e5f219ab5

Above are the 2 files i can access, am i supposed to be able to access the .gz?

Can you provide a modlist, so I can try to reproduce the issue?

Mod list inc. versions

Aquaculture-1.16.4-2.1.11.jar
ars_nouveau-1.16.4-1.10.6.jar
BiomesOPlenty-1.16.4-13.0.0.427-universal.jar
BotanyPots-1.16.4-6.0.7.jar
chiselsandbits-0.2.8-RELEASE.jar
curios-forge-1.16.4-4.0.3.3.jar
ftb-chunks-1604.2.2.57.jar
ftb-gui-library-1604.1.1.26.jar
forge-1.16.4-geckolib-3.0.0.jar
JustEnoughResources-1.16.4-0.12.0.103.jar
Mekanism-1.16.4-10.0.18.445.jar
MekanismAdditions-1.16.4-10.0.18.445.jar
MekanismGenerators-1.16.4-10.0.18.445.jar
MekanismTools-1.16.4-10.0.18.445.jar
OresAboveDiamonds-1.16.4-v6.3.1.jar
pamhc2foodcore-1.16.3-1.0.0.jar
performant-1.16.2-4-3.29m.jar
Placebo-1.16.3-4.3.3.jar
Quark-r2.4-291.jar
ScalingHealth-1.16.4-4.0.2+2.jar
SilentGear-1.16.3-2.4.11+200.jar
SilentLib-1.16.3-4.9.0+63.jar
SilentGems-1.16.3-3.7.7+110.jar
TheAbyss 1.0.7 1.16.4.jar
Vampirism-1.16.4-1.7.1.jar
veinmining-forge-1.16.4-0.4.jar
Xaeros_Minimap_20.30.1_Forge_1.16.4.jar
xptome-1.16.2-v1.1.6.jar
abnormals_core-1.16.4-3.0.6.jar
mining_dimension-1.16.4-1.0.3.jar
Apotheosis-1.16.3-4.4.1.jar
AutoRegLib-1.6-47.jar
BasicNetherOres-1.16.4-5.4.0.jar
bspawncontrol_1.16.4-1.1.jar
Bookshelf-1.16.4-9.3.25.jar
Clumps-6.0.0.13.jar
collective-1.16.4-1.53.jar
CookingForBlockheads_1.16.3-9.2.2.jar
corpse-1.16.4-1.0.5.jar
despawningeggshatch_1.16.4-2.0.jar
DungeonCrawl-1.16.3-2.2.4.jar
ftb-essentials-1604.1.0.13.jar
gaiadimension-1.16.4-1.3.1.jar
infernal-expansion-forge-1.2.0.jar
ironchest-1.16.4-11.2.10.jar
jei-1.16.4-7.6.1.65.jar
moredragoneggs-1.4.jar
no-nitwits-1.16.4-1.0.0.jar
pamhc2crops-1.16.3-1.0.1.jar
pamhc2foodextended-1.16.3-1.0.0.jar
pamhc2trees-1.16.3-1.0.0.jar
Patchouli-1.16.4-48.jar
ResourcefulBees1.16.3-1.16.4-0.5.8b.jar
SpawnerFix-1.16.2-1.0.0.2.jar
endergetic-1.16.4-3.0.0.jar
kingvillager-1.6.1.jar
OuterEnd-0.2.3.jar
tnt-yeeter-1.16.4-1.2.0.jar
toolleveling-1.16.2-1.1.1.jar
towers_of_the_wild-1.16.4-2.0.1.jar
valhelsia_structures-16.0.5.jar
WAWLA-1.16.4-7.0.2.jar
Waystones_1.16.3-7.3.1.jar

Thanks for your issue. However, we haven't been able to recreate this bug. Hopefully newer versions of Infernal Expansion and the mods you have listed here will fix the issue.