Yes running in https mode is the problem, I am running in mixed mode.
but if you change the URL to https it will work in https mode, so change
<context-param>
<param-name>zimbra.soap.url</param-name>
<param-value>http://85.17.7.237/service/soap</param-value>
</context-param>
TO
<context-param>
<param-name>zimbra.soap.url</param-name>
<param-value>
https://85.17.7.237/service/soap</param-value>
</context-param>
And it should work.
[]s