# TypeError: Cannot assign to read only property 'undefined' of object '#', did not find any solution in past posts

**URL:** <https://discourse.psychopy.org/t/typeerror-cannot-assign-to-read-only-property-undefined-of-object-did-not-find-any-solution-in-past-posts/38597>\
**Category:** Online experiments\
**Created:** [February 11, 2024, 10:28am UTC](https://discourse.psychopy.org/t/typeerror-cannot-assign-to-read-only-property-undefined-of-object-did-not-find-any-solution-in-past-posts/38597 "2024-02-11T10:28:50Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Yoel\_Sheinenson](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.psychopy.org/yoel_sheinenson/32/40800_2.png) [@Yoel\_Sheinenson](https://discourse.psychopy.org/u/Yoel_Sheinenson)\
**Post date:** [February 11, 2024, 10:28am UTC](https://discourse.psychopy.org/t/typeerror-cannot-assign-to-read-only-property-undefined-of-object-did-not-find-any-solution-in-past-posts/38597/1 "2024-02-11T10:28:50Z")

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URL of experiment: [experiment [PsychoPy]](https://run.pavlovia.org/YoelSh/experiment)

Description of the problem:  
My experiment run locally on my computer. It begins to run online, but when it tries enters a loop, it crashes with the error: “TypeError: Cannot assign to read only property ‘undefined’ of object ‘#’”.  
There are no empty columns on my csv files, creating a new conditions files does not solve this problem.  
does anyone know what can fix this?