What is the ruling on someone who had a wet dream during the daytime in Ramadan and broke their fast, thinking that a wet dream invalidates the fast?

Ignorance of the rulings of Sharia (definition) leads to grave transgressions, and seeking sacred knowledge is obligatory so that a servant may worship his Lord with insight. Repentance is due for negligence in seeking the obligatory knowledge, for learning what makes one's worship valid is an individual obligation (fard ayn). A wet dream during the daytime in Ramadan (definition) does not invalidate the fast. The day that was broken must be made up.