PI2.1:invalid cli credentials for password only login devices

Question

Hi,
We've got in trouble with a LMS to PI Migration maybe because the target devices are configured for Telnet
with a password only Login in place of the the common username Password Login Dialog in this Network.
LMS seams to can handle a Password only Login CLI Dialog with all of the devices but Prime Infrastructure claims "invalid cli credentials" for most devices but it seams to work with a lower part of the devices.
What can we do that PI can handle CLI login with Password only Dialog for all devices? Customer dont want to reconfiger the Network devices for username Password Login. 
Steffen

Answer 1

Hi Afroy,
Thx for your reply. Its not a question of wrong credentials. I tested exevry thing from ade+ commandline. I used a converted csv-export from LMS (where all devices was working). The problem is PI only related:
all devices in question are:
- SNMP reachable, because green check mark in device work center, but name and type is empty despite SNMP discovered infos and OID + name is written into the discovery=>reachable log if I try to discover this devices
- unmanaged, because claiming "wrong cli credential"
- ifm_inventory.log has some following dissent for all this devices:
postCollection() ... Cache status: false.
Error logging - Device <ip> Updated Successfully
delete and re-add this devices brings no improvement.
Steffen