# Error in notebook

**URL:** <https://community.deeplearning.ai/t/error-in-notebook/277042>\
**Category:** Sequences, Time Series and Prediction\
**Tags:** week-module-4\
**Created:** [February 19, 2023, 7:47pm UTC](https://community.deeplearning.ai/t/error-in-notebook/277042 "2023-02-19T19:47:52Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![Osama\_Saad\_Farouk](https://sea1.discourse-cdn.com/dlai/user_avatar/community.deeplearning.ai/osama_saad_farouk/32/32413_2.png) [@Osama\_Saad\_Farouk](https://community.deeplearning.ai/u/Osama_Saad_Farouk)\
**Post date:** [February 19, 2023, 7:47pm UTC](https://community.deeplearning.ai/t/error-in-notebook/277042/1 "2023-02-19T19:47:52Z")

</div>

![image](https://global.discourse-cdn.com/dlai/original/3X/0/7/07a5edcfdcbdea1eebe10e17b42f6d27b0de997f.png)

I get this error of incompatible shapes and this is a mistake in the notebook as I don’t write any code here.

---

<div class="post-metadata">

**Author:** ![ai\_curious](https://sea1.discourse-cdn.com/dlai/user_avatar/community.deeplearning.ai/ai_curious/32/128003_2.png) [@ai\_curious](https://community.deeplearning.ai/u/ai_curious)\
**Post date:** [February 19, 2023, 8:43pm UTC](https://community.deeplearning.ai/t/error-in-notebook/277042/2 "2023-02-19T20:43:07Z")

</div>

What created _true\_series_ and _forecast_ and are you sure these have the correct shapes when they are passed into _mean\_squared\_error()_ ?