Report freezes using custom map json

Does anybody have a solution to below problem please?

I have created a report and added a map visual to it. It needs to display custom regions to I selected a json file, but this turned out to be the wrong file. The result is that the report tries loading the data in the visual everytime I open the report, but it freezes (I suppose due to an overload of map details).

Is there some way to remove the visual (or the reference to the json file) outside of Power BI desktop? Or another way to get around this problem?

Your help is appreciated!

Kind regards,

Barry