Can't place modded blocks in my server

[Nyxistaken]

Hello! I am still very new to creating servers but today I was trying to make one so that me and my brother could play with mods.
I created a forge server and allowed it to install, I also made a run.bat file though had to delete it afterwards as it stopped working, not sure why. Now the server itself does work, but whenever I try to place a modded block it just seems to vanish
here are my latest logs: 
[19:21:45] [Server thread/INFO]: Starting minecraft server version 1.12.2
[19:21:45] [Server thread/INFO]: Loading properties
[19:21:45] [Server console handler/ERROR]: Exception handling console input
java.io.IOException: The handle is invalid
    at java.io.FileInputStream.readBytes(Native Method) ~[?:?]
    at java.io.FileInputStream.read(Unknown Source) ~[?:?]
    at java.io.BufferedInputStream.read1(Unknown Source) ~[?:?]
    at java.io.BufferedInputStream.read(Unknown Source) ~[?:?]
    at sun.nio.cs.StreamDecoder.readBytes(Unknown Source) ~[?:?]
    at sun.nio.cs.StreamDecoder.implRead(Unknown Source) ~[?:?]
    at sun.nio.cs.StreamDecoder.read(Unknown Source) ~[?:?]
    at java.io.InputStreamReader.read(Unknown Source) ~[?:?]
    at java.io.BufferedReader.fill(Unknown Source) ~[?:?]
    at java.io.BufferedReader.readLine(Unknown Source) ~[?:?]
    at java.io.BufferedReader.readLine(Unknown Source) ~[?:?]
    at nz$2.run(SourceFile:100) [minecraft_server.1.12.2.jar:?]
[19:21:45] [Server thread/INFO]: Default game type: SURVIVAL
[19:21:45] [Server thread/INFO]: Generating keypair
[19:21:45] [Server thread/INFO]: Starting Minecraft server on 192.168.0.150:25565
[19:21:45] [Server thread/INFO]: Using default channel type
[19:21:46] [Server thread/INFO]: Preparing level "world"
[19:21:46] [Server thread/INFO]: Loaded 488 advancements
[19:21:46] [Server thread/INFO]: Preparing start region for level 0
[19:21:47] [Server thread/INFO]: Preparing spawn area: 48%
[19:21:48] [Server thread/INFO]: Done (1.771s)! For help, type "help" or "?"
[19:22:01] [User Authenticator #1/INFO]: UUID of player Nyxistaken is 0609cbac-80f9-45a0-8fe0-0c261d3ef31b
[19:22:01] [Server thread/INFO]: Nyxistaken[/192.168.0.150:55368] logged in with entity id 190 at (37.5, 63.0, 252.5)
[19:22:01] [Server thread/INFO]: Nyxistaken joined the game
[19:22:33] [Server thread/INFO]: Set Nyxistaken's game mode to Survival Mode
[19:22:47] [Server thread/INFO]: Set Nyxistaken's game mode to Creative Mode

I have about 13 mods that I am using including an NPC mod and the Aether mod. My brother has these installed as well, I have them installed on my main game and in the server folder so I'm not sure why it isn't working

[Crazzy4999]

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

[Nyxistaken]

Alright, but I don't think any of the server stuff changes too much with the version, I just need a hand

[Crazzy4999]

I don't know if anything change or not most likely it changes but you still won't get any help and the topic will be closed

[Huskabyte]

Are your mod(s) installed both on the client and server side?

 

Nevermind, just found my answer

Edited August 15, 2020 by Huskabyte
Realized the answer was in your original post.

[Huskabyte]

Ah! Wait! Are you running the wrong server jar? You need to run the forge jar file using a command prompt or terminal of sorts, not the minecraft server jar file.

[Danebi]

1 hour ago, Nyxistaken said:

[19:21:45] [Server thread/INFO]: Starting minecraft server version 1.12.2
[19:21:45] [Server thread/INFO]: Loading properties
[19:21:45] [Server console handler/ERROR]: Exception handling console input
java.io.IOException: The handle is invalid
    at java.io.FileInputStream.readBytes(Native Method) ~[?:?]
    at java.io.FileInputStream.read(Unknown Source) ~[?:?]
    at java.io.BufferedInputStream.read1(Unknown Source) ~[?:?]
    at java.io.BufferedInputStream.read(Unknown Source) ~[?:?]
    at sun.nio.cs.StreamDecoder.readBytes(Unknown Source) ~[?:?]
    at sun.nio.cs.StreamDecoder.implRead(Unknown Source) ~[?:?]
    at sun.nio.cs.StreamDecoder.read(Unknown Source) ~[?:?]
    at java.io.InputStreamReader.read(Unknown Source) ~[?:?]
    at java.io.BufferedReader.fill(Unknown Source) ~[?:?]
    at java.io.BufferedReader.readLine(Unknown Source) ~[?:?]
    at java.io.BufferedReader.readLine(Unknown Source) ~[?:?]
    at nz$2.run(SourceFile:100) [minecraft_server.1.12.2.jar:?]
[19:21:45] [Server thread/INFO]: Default game type: SURVIVAL
[19:21:45] [Server thread/INFO]: Generating keypair
[19:21:45] [Server thread/INFO]: Starting Minecraft server on 192.168.0.150:25565
[19:21:45] [Server thread/INFO]: Using default channel type
[19:21:46] [Server thread/INFO]: Preparing level "world"
[19:21:46] [Server thread/INFO]: Loaded 488 advancements
[19:21:46] [Server thread/INFO]: Preparing start region for level 0
[19:21:47] [Server thread/INFO]: Preparing spawn area: 48%
[19:21:48] [Server thread/INFO]: Done (1.771s)! For help, type "help" or "?"
[19:22:01] [User Authenticator #1/INFO]: UUID of player Nyxistaken is 0609cbac-80f9-45a0-8fe0-0c261d3ef31b
[19:22:01] [Server thread/INFO]: Nyxistaken[/192.168.0.150:55368] logged in with entity id 190 at (37.5, 63.0, 252.5)
[19:22:01] [Server thread/INFO]: Nyxistaken joined the game
[19:22:33] [Server thread/INFO]: Set Nyxistaken's game mode to Survival Mode
[19:22:47] [Server thread/INFO]: Set Nyxistaken's game mode to Creative Mode

This is a vanilla server. To start a modded server you have to start the forge jar.

[Nyxistaken]

59 minutes ago, Danebi said:

This is a vanilla server. To start a modded server you have to start the forge jar.

I just figured that out with a video, but when I try to launch the forge jar this is what I get
 

C:\Users\Filip\Desktop\Minecraft Server>java -Xmx4096M -Xms4096M -jar forgeserver.jar nogui
A problem occurred running the Server launcher.java.lang.reflect.InvocationTargetException
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.base/java.lang.reflect.Method.invoke(Unknown Source)
        at net.minecraftforge.fml.relauncher.ServerLaunchWrapper.run(ServerLaunchWrapper.java:70)
        at net.minecraftforge.fml.relauncher.ServerLaunchWrapper.main(ServerLaunchWrapper.java:34)
Caused by: java.lang.ClassCastException: java.base/jdk.internal.loader.ClassLoaders$AppClassLoader cannot be cast to java.base/java.net.URLClassLoader
        at net.minecraft.launchwrapper.Launch.<init>(Launch.java:34)
        at net.minecraft.launchwrapper.Launch.main(Launch.java:28)
        ... 6 more

C:\Users\Filip\Desktop\Minecraft Server>PAUSE
Press any key to continue . . .

and that's after having changed the file name to forgeserver and the run task to forgeserver.jar 
If I keep the same names as default on run.bat I end up with a "click a key to continue" without any other info
the thing just doesn't launch

[Danebi]

What version of java do you have?

[Nyxistaken]

35 minutes ago, Danebi said:

What version of java do you have?

I'm not sure, I installed it quite a wee while ago. Tbh I haven't touched MC until a few weeks ago when my brother bought it, hence why I wanted to make a server with mods (LAN connection kept timing out or having weird errors)

[Nyxistaken]

Downloaded the latest version and now I am getting this:
 

C:\Users\Filip\Desktop\Minecraft Server>java -Xmx4096M -Xms4096M -jar forgeserver.jar nogui
Invalid maximum heap size: -Xmx4096M
The specified size exceeds the maximum representable size.
Error: Could not create the Java Virtual Machine.
Error: A fatal exception has occurred. Program will exit.

C:\Users\Filip\Desktop\Minecraft Server>PAUSE
Press any key to continue . . .

[Danebi]

Have you installed java 32 bit or 64 bit?

Edited August 15, 2020 by Danebi

[Huskabyte]

I also believe Minecraft is best on Java 8.

[Nyxistaken]

I’m not sure. I think 64? Also I was able to manually open the forge server file this time, though after a few minutes the client crashes without showing any error messages 

[Danebi]

I'm pretty sure you have java 32 bit. You can check using java -version

And if your game crashed post debug.log.

Edited August 15, 2020 by Danebi