Incorrect Parameter on Belkin Modem

Today I have a customer setting up his Belkin Modem but getting an error message ADSL Incorrect Parameter. This is the first time that I encounter a message when setting up a certain modem. The modem is almost a year old and he said that he's been setting up the modem and he knows the correct settings. The first thing I check was the settings thinking that he might put the wrong setup. Reviewing the setting and running a wizard are all correct but when saving the setting a pop up message shows up “ADSL Incorrect parameter”. ADSL setting requires username, password and certain Internet Service

Provider set up. I check and try removing he username and it shows a different error. Resetting the modem to factory condition won’t help as my customer told me that he already did. Checking the last option on the case I told him that it could be an issue with the modem firmware. He told me that he was about to call Belkin for help but he try ISP first. The case is being monitored to check what will happen on his Belkin Modem although the issue is not resolve customer understand that it could be a modem problem