خطا:IntegrityError at /register

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IntegrityError at /register
UNIQUE constraint failed: auth_user.username
Request Method:	POST
Request URL:	http://127.0.0.1:8000/register
Django Version:	3.2.4
Exception Type:	IntegrityError
Exception Value:	
UNIQUE constraint failed: auth_user.username
Exception Location:	C:\Users\hp_pc\Desktop\shop\venv\lib\site-packages\django\db\backends\sqlite3\base.py, line 423, in execute
Python Executable:	C:\Users\hp_pc\Desktop\shop\venv\Scripts\python.exe
Python Version:	3.7.0
Python Path:	
['C:\\Users\\hp_pc\\Desktop\\shop',
 'C:\\Users\\hp_pc\\Desktop\\shop',
 'C:\\Program Files\\JetBrains\\PyCharm '
 '2021.1.1\\plugins\\python\\helpers\\pycharm_display',
 'C:\\Users\\hp_pc\\Desktop\\shop\\venv\\Scripts\\python37.zip',
 'C:\\Users\\hp_pc\\AppData\\Local\\Programs\\Python\\Python37\\DLLs',
 'C:\\Users\\hp_pc\\AppData\\Local\\Programs\\Python\\Python37\\lib',
 'C:\\Users\\hp_pc\\AppData\\Local\\Programs\\Python\\Python37',
 'C:\\Users\\hp_pc\\Desktop\\shop\\venv',
 'C:\\Users\\hp_pc\\Desktop\\shop\\venv\\lib\\site-packages',
 'C:\\Program Files\\JetBrains\\PyCharm '
 '2021.1.1\\plugins\\python\\helpers\\pycharm_matplotlib_backend']
Server time:	Mon, 21 Jun 2021 18:04:18 +0000