It seems this spell does not recognize the Paladins spellcasting ability.
It works for Druids and Clerics just fine, but for Paladins when putting it onto their sheets it is "+0", my Paladin has 20 Charisma, uses Charisma for casting, so it's +4.
So somehow it does not recognize that "base" for Paladins is CHA.
Make sure that your default spellcasting is set for CHA in your preparation. Sometimes in creating a character this can get messed up initially.
Ruleset?
Ah, found it out. In the group i need to set CHA as Ability. I just don't know why it didnt do that automatically or why it got lost (in case of the Wizard who suddenly only had DC 10).
Ruleset is 5E.
The spellcasting ability is fixed when you drag in the class to the character sheet. FG knows that a Paladin uses Charisma as their spellcasting ability as it does for all classes. However it is possible to confuse the issue if players start to mess around with their characters and possibly amend something that they shouldn't or perhaps delete a class and add a new one.