Good you figured that out!
Some advices that helped me a lot though.
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Get the fingering straight and remember to use the ring finger first on A4 and Pinky the second time on A4. this feels much easier to me at least.
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Do it SLOOOOOOOOOW and just get used to the shape. If spacing is too hard, you may try it on higher frets first, maybe 7&9.
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I started doing BJ as a warm up when I progressed through the course and whenever I picked up the bass I was just doing this as an excersie while Josh introduced new modules to me.