🚨 [Bug] I can't connect todolist search api between Frontend and Backend

[orieasy1]

🚨 Issue Checklist

• Issue Title: [BUG] 'Detailed bug description'
• Add Assignees and Labels.

🐛 Bug Overview

• This bug has occurred.
• I can connect. Error comes out
  

🐞 Detailed Bug Description

• Steps to reproduce the bug: We schould check frontend and backends' json type
• The problem seems to occur in this file or code section.

✅ TODO

• To fix this, we need to do the following: Code review between teamates
• Also, this task might be required.

[seoha376]

We discussed hard about this topic, but it was difficult to solve at that time... The problem is worth to be talked together again!