When performing 'Forgot password' flow, 'AccountName' provided is case-sensitive and if the user does not provide the account name in exact similar cases, the user gets below error message:

"The information provided is invalid. Please try again."


For example, if AccountName stored in 'AccountName', you cannot perform 'Forgot Password' flow user accountnames such as:
ACCOUNTNAME, accountname, Accountname. It has to be AccountName.

However, it is not same experience when doing standard login, as the UserName field on login screen is case insensitive.
 

1. It only applies when using ‘Account Name’ as Primary Attribute to Identify Users. ‘User Name’ on ‘Forgot Password’ screen is still case sensitive.
2. It only applies to ActiveDirectory supported authentication sources.