Remove \n and re.DOTALL and also add strip()
\n
re.DOTALL
strip()
Snippet:
time_stamp, messages = re.findall(r'(\d+/\d+/\d+ \d\d:\d\d:\d\d[.]\d\d\d\d)(.*)', line)[0]
And:
print(f'time_stamp: {time_stamp}, message: {messages.strip()}')