JaariAtmc

It is needed.

I am not getting this message. Other than that you should change the ?dl=0 to ?dl=1.

Delete the DimensionalDoors folder from your server's world save. Restart the server.

Install and use this java. https://javadl.oracle.com/webapps/download/GetFile/1.8.0_251-b08/3d5a2bb8f8d4428bbe94aed7ec7ae784/unix-i586/jdk-8u251-macosx-x64.dmg

Looks like you aren't allocating enough memory/ you are allocating too much memory. How much RAM out of your total RAM are you allocating?

Please pastebin your technic log, or request help in the Technic discord.

Make sure you are actually using 8u251 (downloaded from link) and not 8u261 which causes your issue.

Use this java instead. https://javadl.oracle.com/webapps/download/GetFile/1.8.0_251-b08/3d5a2bb8f8d4428bbe94aed7ec7ae784/unix-i586/jdk-8u251-macosx-x64.dmg

What Forge version and universal or installer?

You have not provided any logs in your own thread.

Why did you include 1.12.2.json in your bin folder? What forge did you include? Universal or Installer?

Use this java instead. Do not use 8u261. https://javadl.oracle.com/webapps/download/AutoDL?BundleId=242044_3d5a2bb8f8d4428bbe94aed7ec7ae784

Install and use this java instead. Do not use Java 8u261. https://javadl.oracle.com/webapps/download/AutoDL?BundleId=242044_3d5a2bb8f8d4428bbe94aed7ec7ae784

Forge 2854 requires you to use the Forge Installer. Rename the Installer as is. Do NOT extract/install.

Please provide a screenshot of your launcher window.

Your CreativeCore is quite outdated, I suggest updating that. https://www.curseforge.com/minecraft/mc-mods/creativecore/files

^For anyone wondering.

You need to download the Offline Installer (64bit). The online installer always downloads and installs 32 bit java.

Do not use the Universal for Forge 1.13+. Use the installer instead. ONLY rename the installer to modpack.jar. Do NOT extract/install.

"i had to force close my computer." And there's your issue. DimensionalDoors (the weird door portals in the overworld leading to a dark maze) dimensions tend to get corrupted if the world is suddenly closed. The fix is easy though. Go to %appdata%\roaming\.technic\modpacks\tekkitmain\saves and open your world save, then delete the Dimdoors/Dimensionaldoors folder inside there. You should be able to play your world again after that.

Download link for 8u51: https://javadl.sun.com/webapps/download/AutoDL?BundleId=107944

Install and use this java instead. https://javadl.oracle.com/webapps/download/GetFile/1.8.0_251-b08/3d5a2bb8f8d4428bbe94aed7ec7ae784/unix-i586/jdk-8u251-macosx-x64.dmg

Its not much performance vs performance thing, but more "is it compatible with what I run" thing. Thermos is slightly less old than Kcauldron.

Spigot is vanilla only. You'll be looking at Kcauldron or Thermos. Both have their issues as well.