Problem or Question:
Users with normal password are being authenticated successfully but some users with special characters in their password fail to authenticate.
Those special characters in the password contains for example, $$ or + (plus) or %%.
This can happen when the password field in the login.fcc is not in upper case.
The default login.fcc has the following:
<input type="password" name="PASSWORD" size="30" style="margin-left: 1px">
If the password field name is not upper case PASSWORD, for example as below, the user password containing special characters will fail to authenticate.
<input type="password" name="password" size="30" style="margin-left: 1px">
This is also true when customer is using additional user attributes to authenticate the user.
You will then append the additional user attributes to the PASSWORD attribute in the login.fcc as sample below.
The PASSWORD and %PASSWORD% have to be in upper case.