How do I solve it?
You could check what user you currently are:
then you could check the permissions of the file:
ls -l bin/
Hopefully this identifies the problem, and then you can adjust the permission accordingly.
In *nix systems, files you want to execute need executable permission. As you can see, there is no executable permission. You should grant executable permission to the file. You can use google to find the answer to how to do this
chmod a+x file1 file2 (Give execute permission to everybody)
In this case:
chmod a+x bin/wdio-test