Cdsapi era5 download error

Hi all,
I am trying to download hourly data in era5 single pressure level, everything is fine until 10h ago. all requests I submit has been held in queue,I dont know why

import cdsapi
from tqdm import tqdm
from datetime import datetime

dataset = "reanalysis-era5-single-levels"
client = cdsapi.Client()
f = open('time_download_surface.txt', 'r')
time_all = f.readlines()
f.close()

for time in tqdm(time_all, desc='total process '):
    time_str = time.replace("\n", "").replace('\r', "").replace(' ', "")
    time_date = datetime.strptime(time_str, '%Y%m%d%H%M')
    time_year = time_date.strftime("%Y")
    time_month = time_date.strftime("%m")
    time_day = time_date.strftime("%d")
    time_time = time_date.strftime("%H:%M")
    request = {
        "product_type": ["reanalysis"],
        "variable": [
            "10m_u_component_of_wind",
            "10m_v_component_of_wind",
            "2m_temperature",
            "mean_sea_level_pressure"
        ],
        'year': [time_year],
        'month': [time_month],
        'day': [time_day],
        "time": [time_time],
        "data_format": "netcdf",
        "download_format": "unarchived",
        "area": [50, 100, -10, 190]
    }
    client.retrieve(dataset, request).download(time_str + '.nc')

time_download_surface.txt has nearly 20k line for my own dataset, is the frequent requests cause this probelm?

I have deleted about 1k requests in my website, it suddenly go back to work, i still dont know why. Is it because my submission time is not good, or because there cannot be too many requests in my account