Migration from 8.6

[RonaldF]

I'm trying to migrate clients from 8.6 to 9.2.2.

When using the Migration Manager I receive the following message

launchpad error (Error code = 2):
== STDERR ====================
Invalid handle passed
==============================

so I tried to do this by backup and restore.

I created a backup on the 8.6 server, transferred it to the 9.2.2 server and converted it.
I created a new client with the same credentials.
In the backup menu I chose the converted backup, selected the appropriate options and started it.

But I only receive a connection timeout/abort (not a plesk message but a simple browser message)

Any help?