Issue with executing steamcmd

I installed FEX using the quick start command in the read.me, I also installed SteamCMD and checked that the files are there. However if I try executing steamcmd.sh I get the following error:

```
Invalid or Unsupported elf file.
This is likely due to a misconfigured x86-64 RootFS
Current RootFS path set to ''
RootFS path doesn't exist. This is required on AArch64 hosts
Use FEXRootFSFetcher to download a RootFS
```

I tried both using the rootfs as extracted and "as is" using FEXRootFSFetcher. I use Ubuntu 22.04.4 on a free tier oracle server, if this helps.
The content of the Config.json file is : `{"Config":{"RootFS":"Ubuntu_22_04"}}`
There is also a folder `/home/ubuntu/.fex-emu/RootFS/Ubuntu_22_04` with contents that look like an Ubuntu image.

Thank you for any help.