It's not possible to use multiple voice chat mods or a voice chat mod and Geyser on the same server because both of them require their own UDP port, and we only provide one port per server.

Aternos supports the following voice chat mods:
- Gliby's Voice Chat Reloaded for Minecraft versions between 1.8.9 and 1.12.2
- Simple Voice Chat for 1.15+ using Spigot, Paper, Forge or Fabric
- Plasmo Voice for Spigot, Paper, Forge and Fabric

To run the voice server, these mods/plugins need an open port on your Minecraft server.

Gilby's Voice Chat Reloaded and Plasmo Voice don't need to be configured for this, since they use your server port by default. You only need to install it on your PC and the server.

Simple Voice Chat can also do this, but it isn't enabled by default. 

Configuring Simple Voice Chat

To generate the configs, you first need to install the mod and then start your server. After that, you need to stop the server again. It's important that your server is offline while you change the config because the mod will overwrite it otherwise.

If you're using forge, you can find the mod's config file by opening your world folder and clicking on 'serverconfig'. The file you want to edit is named 'voicechat-server.toml'.

For Fabric servers, that file can be found by going to files, then config, voicechat, and opening voicechat-server.properties. If you're using Paper or Spigot it's located in plugins, voicechat, voicechat-server.properties.

Here, you want to change 'port = 24454' to 'port = -1'. Now you just need to start your server again, and you can use the voice chat.