I've encountered an issue on anaconda python on windows 10 v1909 which I suspect is related. It looks like no dates in 1970 can be converted to datetime.timestamp():

Python 3.8.2 (default, Apr 14 2020, 19:01:40) [MSC v.1916 64 bit (AMD64)]
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IPython 7.13.0 -- An enhanced Interactive Python. Type '?' for help.

In [1]: import datetime

In [2]: datetime.datetime(1970, 1, 2, 0, 0, 1, 123456).timestamp()
---------------------------------------------------------------------------
OSError                                   Traceback (most recent call last)
<ipython-input-2-0ac473af013b> in <module>
----> 1 datetime.datetime(1970, 1, 2, 0, 0, 1, 123456).timestamp()

OSError: [Errno 22] Invalid argument

In [3]: datetime.datetime(1971, 1, 2, 0, 0, 1, 123456).timestamp()
Out[3]: 31618801.123456