Hello Paolo,
By this: "..in a company 's upgrade CUCM 8 to CUCM 9 for this part only 20 devices were migrated with their respective line settings" AND "Set the current environment is that users are production CUCM 8 and CUCM 9 there are 20 , they communicate with each other by a trunk ( trunk intercluster )"
If i understood this right you have actually two different CUCM servers connected via a trunk (cucm 8.x --inter cluster trunk-- cucm 9.x)
By this: "even though number is routed to the mailbox does not reach the user box , a way to fix this is to delete the configuration of the box and recreate it , but with this other fault occurs and is not receiving the alert that they have a voice"
It seems calls reach CUC but not to the intended migrated voicemails box and if you recreate the voicemail box for the user the MWI (Message Waiting Indicator) stops working.
Based on the screenshot it looks like you have an AXL integration.
To me your call flow deployment looks somewhat like this:
CUC - sccp/sip- CUCM 8.x -trunk- CUCM 9.x && CUC -axl- CUCM 8.x
So you would basically have only one Phone System on CUC integrated with CUCM 8.x.
My recommendation for the MWI issue would be to create a second Phone System that integrates also with CUCM 9.x use just a couple of ports to test it out, this of course also along a paralell Hunt Pilot that will reach those test ports. This is to avoid trying to send the MWI notification via the inter-cluster trunk.
Now for the user recreation part, do you re-import them via axl or just create them locally, if done locally i would probably say it's due to tied tables with the CUCM 8.x server.
This is the only i can think right now, any additional input you can share will be appreciated.
-davrojpec