Why can't I handle 300 get responses with async? - asynchronous

Question

As part of my homework project, I'm working with imdb.com pages.
For one task I need to make 320 get-requests to turn them into beautifulsoup objects later on.
I'm trying to do that the async way and so far I got this:
def get_tasks(session, url_links):
tasks = []
num = 1 # debugging purposes
for url in url_links:
tasks.append(session.get(url, headers={'Accept-Language': 'en', 'X_FORWARDED_FOR': '2.21.184.0'}, ssl=False))
time.sleep(1) # avoid 503 status_code
print(f"Number of responses get_tasks: {num}") # debugging purposes
num += 1 # debugging purposes
return tasks
# Getting response.texts
results = []
async def get_response_texts(url_links):
async with aiohttp.ClientSession() as session:
tasks = get_tasks(session, url_links)
responses = await asyncio.gather(*tasks)
t1 = time.perf_counter()
num = 1
for response in responses:
results.append(await response.text())
print(f"{num} responses processed") # debugging purposes
num += 1
t2 = time.perf_counter()
print(f'Asynchronous execution: Finished in {t2 - t1} seconds\n')
if __name__ == '__main__':
links = [a list of urls to films as strings]
asyncio.run(get_response_texts(links))
print(len(results))
Here comes the problem: When I process 100 requests, things seem all right, but when I make 300, I get asyncio.exceptions.TimeoutError.
Why is it so and how can I avoid that and make 320 requests asynchronously?