FastApi uvicorn server not connecting to localhost - python-3.x

Question

I am trying FASTAPI with the code below and localhost is not reachable with 127.0.0.1:8000 or localhost:8000 also. Tried setting with different port numbers also.
At the end it says
NameError: name '_TypeAliasForm' is not defined
This is on windows 10 with python 3.10
from fastapi import FastAPI
app = FastAPI()
#app.get("/")
async def root():
return {"message": "Hello World"}
PS G:\pyproj\fastapiex> uvicorn main:app --reload
←[32mINFO←[0m: Will watch for changes in these directories: ['G:\\pyproj\\fastapiex']
←[32mINFO←[0m: Uvicorn running on ←[1mhttp://127.0.0.1:8000←[0m (Press CTRL+C to quit)
←[32mINFO←[0m: Started reloader process [←[36m←[1m6936←[0m] using ←[36m←[1mwatchgod←[0m
Process SpawnProcess-1:
Traceback (most recent call last):
File "c:\users\jsl\appdata\local\programs\python\python310\lib\multiprocessing\process.py", line 315, in _bootstrap
self.run()
File "c:\users\jsl\appdata\local\programs\python\python310\lib\multiprocessing\process.py", line 108, in run
self._target(*self._args, **self._kwargs)
File "c:\users\jsl\appdata\local\programs\python\python310\lib\site-packages\uvicorn\subprocess.py", line 76, in subprocess_started
target(sockets=sockets)
File "c:\users\jsl\appdata\local\programs\python\python310\lib\site-packages\uvicorn\server.py", line 68, in run
return asyncio.run(self.serve(sockets=sockets))
File "c:\users\jsl\appdata\local\programs\python\python310\lib\asyncio\runners.py", line 44, in run
return loop.run_until_complete(main)
File "c:\users\jsl\appdata\local\programs\python\python310\lib\asyncio\base_events.py", line 641, in run_until_complete
return future.result()
File "c:\users\jsl\appdata\local\programs\python\python310\lib\site-packages\uvicorn\server.py", line 76, in serve
config.load()
File "c:\users\jsl\appdata\local\programs\python\python310\lib\site-packages\uvicorn\config.py", line 448, in load
self.loaded_app = import_from_string(self.app)
File "c:\users\jsl\appdata\local\programs\python\python310\lib\site-packages\uvicorn\importer.py", line 21, in import_from_string
module = importlib.import_module(module_str)
File "c:\users\jsl\appdata\local\programs\python\python310\lib\importlib\__init__.py", line 126, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "<frozen importlib._bootstrap>", line 1049, in _gcd_import
File "<frozen importlib._bootstrap>", line 1026, in _find_and_load
File "<frozen importlib._bootstrap>", line 1005, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 698, in _load_unlocked
File "<frozen importlib._bootstrap_external>", line 832, in exec_module
File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
File ".\main.py", line 1, in <module>
from fastapi import FastAPI
File "c:\users\jsl\appdata\local\programs\python\python310\lib\site-packages\fastapi\__init__.py", line 7, in <module>
from .applications import FastAPI as FastAPI
File "c:\users\jsl\appdata\local\programs\python\python310\lib\site-packages\fastapi\applications.py", line 3, in <module>
from fastapi import routing
File "c:\users\jsl\appdata\local\programs\python\python310\lib\site-packages\fastapi\routing.py", line 20, in <module>
from fastapi import params
File "c:\users\jsl\appdata\local\programs\python\python310\lib\site-packages\fastapi\params.py", line 4, in <module>
from pydantic.fields import FieldInfo, Undefined
File "c:\users\jsl\appdata\local\programs\python\python310\lib\site-packages\pydantic\__init__.py", line 2, in <module>
from . import dataclasses
File "c:\users\jsl\appdata\local\programs\python\python310\lib\site-packages\pydantic\dataclasses.py", line 3, in <module>
from .class_validators import gather_all_validators
File "c:\users\jsl\appdata\local\programs\python\python310\lib\site-packages\pydantic\class_validators.py", line 8, in <module>
from .errors import ConfigError
File "c:\users\jsl\appdata\local\programs\python\python310\lib\site-packages\pydantic\errors.py", line 5, in <module>
from .typing import display_as_type
File "c:\users\jsl\appdata\local\programs\python\python310\lib\site-packages\pydantic\typing.py", line 23, in <module>
from typing_extensions import Annotated, Literal
File "c:\users\jsl\appdata\local\programs\python\python310\lib\site-packages\typing_extensions.py", line 1786, in <module>
#_TypeAliasForm
NameError: name '_TypeAliasForm' is not defined