Swimbot Error

Traceback (most recent call last):
  File "C:\Users\wmiller\AppData\Local\Programs\Python\Python39\lib\site-packages\discord\ext\commands\core.py", line 85, in wrapped
    ret = await coro(*args, **kwargs)
  File "c:\Users\wmiller\Desktop\Swimbot\whois.py", line 533, in seen
    last_time = datetime.datetime.strptime(last_time[:19], '%Y-%m-%dT%H:%M:%S%z')
  File "C:\Users\wmiller\AppData\Local\Programs\Python\Python39\lib\_strptime.py", line 568, in _strptime_datetime
    tt, fraction, gmtoff_fraction = _strptime(data_string, format)
  File "C:\Users\wmiller\AppData\Local\Programs\Python\Python39\lib\_strptime.py", line 349, in _strptime
    raise ValueError("time data %r does not match format %r" %
ValueError: time data '2021-03-16T16:28:42' does not match format '%Y-%m-%dT%H:%M:%S%z'