This is within reason to be expected, fineliners are a less forgiving mark making device. (See Lesson 0, Part 4)

See if a new fineliner from the box works better, some can be duds out of the box, others will have become damaged over time.

You could try another brand, to see if they work better for you.

Hold the pen upright.

Confident mark making is a skill Drawabox improves, particularly in the lesson 1.

Complete the lessons to the best of your current ability, independent of outcome. Cultivate serenity.

If you are changing mark marking device half way through lesson 1, redoing the prior line exercises, either once in whole if suitably early in the course or as 15min warmups will help. Avoid grinding (see Lesson 1)

Otherwise the note section of your submission can mention the change in pen.

Complete the lesson and see the feedback you receive.

After lesson 1 just make sure your warmups are done with the fineliner in question.