MSMTC hangs during login with message File /...../msmruntime/tomcat/webapps/MSM/MSMMain.html' does not exist.
Apache Tomcat, z/OS, OMVS
Possible overlay of file system.
Please look in ishell in this path /...../tomcat/webapps/MSM/ to see if you can find MSMMain.html. if it is missing, cancel MSMTC, delete the /MSM directory under /...../msmruntime/tomcat/webapps. Be careful not to delete the MSM.war file then restart MSMTC. On startup MSMTC will rebuild the /MSM directory from the MSM.war file.
Note that tomcat is just a symbolic for apache-tomcat-n.n.nn directory.
CA CSM Administration guide.