Phone number format is invalid. Contact your system administrator (4251002)

When a user uses the Telephone Verification they get the following error

“Phone number format is invalid. Contact your system administrator”

Cause 1

The format of the phone number does not correspond to format specified in the Admin Guide

Cause 2

The format of the phone number does correspond to the format specified in the Admin Guide but there is more than one phone number listed in the multi-value attribute ‘otherTelephone’.

Resolution 1

1. Enter the phone number in the following format ‘+ Country Code-Area Code-Phone Number’
2. Note: The  ‘+’ sign MUST be used. The ‘-‘ sign is optional.
3. See “Authenticate via Phone” for more details

Resolution 2

1. Open the user object properties in Active Directory Users and Computers (ADUC)
2. In the ‘General’ tab click on the ‘Other’ button adjacent to the ‘Telephone Number’ field.
3. Remove all but one of the phone numbers entered.

Test and verify that Telephone Verification works as expected.