I am running VirtualBox Sandbox (2.5). Ambari is running fine, but when I try to reach Zeppelin (port 9995) - I get:
"GET http://127.0.0.1:9995/scripts/vendor.js net::ERR_CONTENT_LENGTH_MISMATCH" in Chrome browser.
Are you accessing zeppelin ui through Zeppelin View or Quick Link from Zeppelin service?
What is the exact URL you have for zeppelin ui?
Read also the below HCC. It is not exactly the same problem as yours however the user had an issue running Zeppelin UI on Sandbox that he managed to fix it.