Getting error

pyfile_1 | Traceback (most recent call last):
pyfile_1 | File "/usr/local/lib/python3.8/site-packages/bottle.py", line 876, in _handle
pyfile_1 | return route.call(**args)
pyfile_1 | File "/usr/local/lib/python3.8/site-packages/bottle.py", line 1756, in wrapper
pyfile_1 | rv = callback(*a, **ka)
pyfile_1 | File "app.py", line 229, in upload
pyfile_1 | f.write((save_dir / str(file_number)).read_bytes())
pyfile_1 | File "/usr/local/lib/python3.8/pathlib.py", line 1229, in read_bytes
pyfile_1 | with self.open(mode='rb') as f:
pyfile_1 | File "/usr/local/lib/python3.8/pathlib.py", line 1222, in open
pyfile_1 | return io.open(self, mode, buffering, encoding, errors, newline,
pyfile_1 | File "/usr/local/lib/python3.8/pathlib.py", line 1078, in _opener
pyfile_1 | return self._accessor.open(self, flags, mode)
pyfile_1 | FileNotFoundError: [Errno 2] No such file or directory: 'chunk/25d9085e-70c8-4f19-9775-15ac4599e0b2/107'

although all chunks have been uploaded

This error comes in bigger files only