Check the log "/opt/splunk/var/log/splunk/web_service.log", and found below error:
WARNING [54cdcd4fcc7f7dec021710] view:361 - An unknown view name "setup" is referenced in the navigation definition for "snmp_ta".
I use the splunk 5.0.2, and snmp_ta app v1.2.7.
Hope for the help. Thanks a lot.
What do you mean by "launch the app" ? The SNMP Modular Input is not an App (doesn't have dashboards , setup pages etc..).
It is accessed via the Data Inputs menu option ie: http://localhost:8000/en-US/manager/launcher/data/inputs/snmp