Despite the poor weather, I was planning on attending the festival with her. No error
The proper idiom for planning an action is planning to do something, not planning on something. Thus, the clause should be "I was planning to attend the festival with him."
940 MCQ for effective preparation of the test of Idioms of English Grammar section.
Read the MCQ statement: Despite the poor weather, I was planning on attending the festival with her. No error, keenly and apply the method you have learn through the video lessons for Idioms to give the answer. Record your answer and check its correct answer and video explanation for MCQ No. 386-4665.