He donated $2.5m and now he wants his money back.
He didn't read the fine print that said up to 60% of the funds would be allocated to Trump's personal legal expenses of 2020, with only 40% actually going to challenge the election. Trumps the con man will always find someone willing to part with their money.
This donor has now realised that Trump was bluffing about the chances of overturning the election.
Trumps group has offered to pay back $1 million if this man drops his legal charges. (So Trump pockets the remainder for his legal expenses in 2020 and beyond).
Trump knows he is going to be in lots of legal fights in a few months, and he will need as much free money as possible to do this.