Check the /opt/amethyst/logs//webadmin.log for the reason.
The Guardian will capture the text out put of the server and write it tot this log:
Error:
Exception Exception in module amt2 at 080BB79C.
Error in TdtxINIFile: /opt/datatex/amtsweeper2/amtsweeper2.ini was modified, but not saved.
If you are setting op the server for the first time, ensure that this file exists. It doesn’t need to contain anything.
mkdir -p /opt/datatex/amtsweeper2/
touch /opt/datatex/amtsweeper2/amtsweeper2.ini