Please check INSTALL.md and README.md to ensure you have all the required dependencies. In particular, you need a version of Chez Scheme compiled with threading support (this is the default in most distributions) in order to run the tests successfully.
* Removing all trace of Idris 2 from your installation directory might help. By default this is `$HOME/.idris2` - if you have a particularly out of date version, or you have used a broken build at some point (as much as we try to avoid this) then deleting this might help.