unable to start containe process

Hello,

I am  trying to build this docker-compose on centos 7. Containers are becoming up. However, I am not able to conenect via cli.
could you please check? 
I am able to login from bash.
thank you

`[root@localhost ~]# docker exec  -it spine-1 Cli
OCI runtime exec failed: exec failed: unable to start container process: exec: "Cli": executable file not found in $PATH: unknown`