Getting Issues in KM after upgrading to 7.3

Hi Friends,

We are getting an issue in KM after upgrading the portal from 7.01 to 7.3 .

In the 7.3 portal the KM navigation is not working and we are unable to access inside any folders in KM.

Also, when trying to import any KM transport , after the upload we are not getting the message "file uploaded"

and the transport file is not showing in pending imports list.

Please help with your suggestions on this.