Forge 1.8.9 Server doesn't work

[HackerBanane]

Hello!

I play Minecraft for many years and I tried to do a Localhost MinecraftForge Server to play LuckyBlock with a friend.

(By the way I am on OSX and my Mac is in German)

I created server for Spigot 1.14.4/ 1.16.3 and Forge 1.16.3.

So I created a localhost server on Minecraft 1.8.9 and the Server started normally,

but if I tried to open the forge-1.8.9-universial.jar file to Install forge on the server like I did it with other Versions there is an error that called (translated from German in English)

"The Java jar file "forge-1.8.9-universal.jar" could not be opened. Check the console for possible error messages"

How can I solve this?

Thanks for any help!

HackerBanane

Edited October 14, 2020 by HackerBanane
some spelling mistakes... I'm from Germany