Vk_api.exceptions.ApiError: [10] Internal server error?

Question

Python

I have a code with a bot for a group that responds to people in PM in python3:
Everything you need is imported, and the group is authorized by token.

while True:
    for event in longpoll.listen():
        messages = vk.method("messages.getConversations", {"offset": 0, "count": 20, "filter": "unanswered"})
        if event.type == VkEventType.MESSAGE_NEW:
            if event.to_me:
                request = event.text
                randint = random.randint(0,900000000)
                request = request.lower()
                chat_id = vk.method('messages.getConversations')
                chat_id = chat_id['items']
                id = messages["items"][0]["last_message"]["from_id"]
                body = messages["items"][0]["last_message"]["text"]
                user = vk.method("users.get", {"user_ids": + id}) 
                fullname = user[0]['first_name'] 
                lastname = user[0]['last_name'] 
                full = user[0]['first_name'] +  ' ' + user[0]['last_name']
                for check in request:
                        if body.lower() == "привет":
                            vk.method("messages.send", {"user_id": id, "message": "[id" + str(id) + "|" + str(fullname) + "],  привет", "random_id": randint})

At some point it throws an error

messages = vk.method("messages.getConversations", {"offset": 0, "count": 20, "filter": "unanswered"})
File "/usr/local/lib/ python3.8/dist-packages/vk_api/vk_api.py", line 684, in method raise
error
vk_api.exceptions.ApiError: [10] Internal server error

The error is not clear why it occurs during normal use. I ask in advance not to tell in words what happened, but to show.