我的代码是这样的

import json
from wechatpayv3 import WeChatPay,WeChatPayType
import settings
import os
import time
import random

client = None
#得到客户端对象。
async def get_client():
    global client
    if client is None:
        cur_dir = os.path.dirname(os.path.abspath(__file__))  # 上级目录
        # 商户证书私钥
        with open(os.path.join(cur_dir,'apiclient_key.pem')) as f:
            PRIVATE_KEY = f.read()
        client= WeChatPay(
            wechatpay_type=WeChatPayType.APP,
            mchid=settings.weixin_config.mch_id,
            private_key=PRIVATE_KEY,
            cert_serial_no=settings.weixin_config.mch_serial_no,
            apiv3_key=settings.weixin_config.mch_key,
            appid=settings.weixin_config.appid,
            notify_url='https://api.21days.cloud/mail/pay/notify/weixin',
            cert_dir=cur_dir,
            logger=settings.logger)
    return client

def getRandom(num):#随机数
    return ''.join(random.choices('ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789',k=num))

async def get_weixin_pay_url(order_number,total_amount,title,ip):
    client=await get_client()
    order_number=str(order_number).replace('-','_')#64个字符以内，仅支持字母、数字 、下划线且需保证在商户端不重复。
    code, message = client.pay(
        description=title or '任务完成奖励',
        out_trade_no=order_number,
        amount={'total': int(total_amount*100)}#订单总金额，单位为分，详见支付金额
    )#见下方统一下单日志

    prepay_id=json.loads(message)['prepay_id']

    sign_data = {'appid': settings.weixin_config.appid,
                 'timestamp': str(int(time.time())),
                 'noncestr':getRandom(24),
                 'prepayid': 'prepay_id='+prepay_id,
                 }
    print(sign_data)#==> {'appid': 'wx3acec2d59bb7e60b', 'timestamp': '1661485406', 'noncestr': 'LV6WBDJRZ48O64AQJBH8CGJS', 'prepayid': 'prepay_id=wx261143266512844af953acbb8606ac0000'}



    sign = client.sign(sign_data)
    settings.logger.info(str(sign))#==> 2022-08-26 11:43:26.749 | INFO     | apps.utils.weixin.payment:get_weixin_pay_url:75 - msrCXfNHCEwNgGpZbpI3J0XWgcraJL4gRQ3+1gxTRf52/eZLmFAaLksNhOZtHlo8tXQbro0XgBo1Ke43FCjIHgFlaBkWzAZPeqezTCygmT1RYu/XAhVN0fhgGXOlZtqZhZcZEz+7VQDtVFiQbg4ysvPwSCOkIyYas0al2X2kxJ4gLxHT7JjVfjEUg1Lgo0JS+/fg3JKOKGXqtimhWDuwC+2gNFTzmvrjVJ+0vjiTXLc1JOGvgCdmBOGg+KKqnfBt8kV4XnFcSxPp3ySqG5gt5Rr5eDvIlYOtv1BhhunbIigFTQkVQQ7hgK9icq2DUpRrFiXPXiWKI2fG1BFdiVkTfg==
    sign_data.update({
        'partnerid':settings.weixin_config.mch_id,
        'package': 'Sign=WXPay',
        'sign': sign,
    })
    return sign_data#见下方返回数据日志

统一下单日志

2022-08-26 11:43:26.402 | DEBUG    | wechatpayv3.core:request:110 - Request url: https://api.mch.weixin.qq.com/v3/pay/transactions/app
2022-08-26 11:43:26.402 | DEBUG    | wechatpayv3.core:request:111 - Request type: POST
2022-08-26 11:43:26.402 | DEBUG    | wechatpayv3.core:request:112 - Request headers: {'Content-Type': 'application/json', 'Accept': 'application/json', 'User-Agent': 'wechatpay v3 api python sdk(https://github.com/minibear2021/wechatpayv3)', 'Authorization': 'WECHATPAY2-SHA256-RSA2048 mchid="1630608186",nonce_str="4B2D084F364B47DA853B2C086C927953",signature="GUYW59jSlQwWs/foZTAnjXu9KaDm/YxSO1h4fcxCYN+OPY89LNYZYusSKpGioabbuHNNFp14iV61Xnt862NG7PRHW4G2qsmS5jQKLhS+cIQlx8tdgCMfi928BFonpDWOHUNsF9DI7sn3ckZQdlvQFp0//t3tMPIP4dbgXjNNM1REO2H/TIyGQ9ToKHR78bJFKoKHH9uXVrxyC8scsEPs1WzBk5BBNfvFycqS8Jy3W74UhOFMJ8E7W9b1eV3LRGg60oz2twtgD9mb2IbMnuENj8DSq2ftLWDfP0sPJcdjOW00wlLya3brvhgGv6XBcISGKthREm/QdR9YA1x9s3XCiA==",timestamp="1661485406",serial_no="52921E8C481362D7C698FDBE8689E153CE35892E"'}
2022-08-26 11:43:26.403 | DEBUG    | wechatpayv3.core:request:113 - Request params: {'notify_url': 'https://api.21days.cloud/mail/pay/notify/weixin', 'description': '学霸养成计划-儿童话筒', 'out_trade_no': '20220822224010228111', 'amount': {'total': 1}, 'appid': 'wx3acec2d59bb7e60b', 'mchid': '1630608186'}
2022-08-26 11:43:26.746 | DEBUG    | wechatpayv3.core:request:127 - Response status code: 200
2022-08-26 11:43:26.746 | DEBUG    | wechatpayv3.core:request:128 - Response headers: {'Server': 'nginx', 'Date': 'Fri, 26 Aug 2022 03:43:26 GMT', 'Content-Type': 'application/json; charset=utf-8', 'Content-Length': '52', 'Connection': 'keep-alive', 'Keep-Alive': 'timeout=8', 'Cache-Control': 'no-cache, must-revalidate', 'X-Content-Type-Options': 'nosniff', 'Request-ID': '08DE82A1980610EC031899B68A4820F4B41428F08C06-0', 'Content-Language': 'zh-CN', 'Wechatpay-Nonce': 'c51908177b3a2e654f50ff8b88c8c817', 'Wechatpay-Signature': 'k60jpew7mlcZp91SVxv86VsSebaqBfvXsQ9nzMjrYzl+guXzs2W1etoUKlPHu92Np/y1Xw1FhWThQDKlyo0lnY/7cyaor3NoD5ThkhTBr+iwZ/XLfdPZMawqa0P3Lll5lTKw9g8RVU44qGl5I12RcJsAfmTi1KG3kGFlYWQmdx6ArcZPuHkDVCgDuM+bKiXvAtN6Ku4dcPnH3xCvbC8tZf3I65qy2NxtiNQIg/jV4Dhqsxt87wQ+vu0iU+5lG+Noaj46u6NChrvpYI4ZByyQm9iz2FafH8gk2tXG6l2OHmoWs4gEybtXp6biMVhKeie92FrO0ycARW2jlk6yJ8mBOg==', 'Wechatpay-Timestamp': '1661485406', 'Wechatpay-Serial': '740C035ED1E90599CDD648697E0C095B82210D26', 'Wechatpay-Signature-Type': 'WECHATPAY2-SHA256-RSA2048'}


返回数据日志
{'appid': 'wx3acec2d59bb7e60b', 'timestamp': '1661485406', 'noncestr': 'LV6WBDJRZ48O64AQJBH8CGJS', 'prepayid': 'prepay_id=wx261143266512844af953acbb8606ac0000', 'partnerid': '1630608186', 'package': 'Sign=WXPay', 'sign': 'msrCXfNHCEwNgGpZbpI3J0XWgcraJL4gRQ3+1gxTRf52/eZLmFAaLksNhOZtHlo8tXQbro0XgBo1Ke43FCjIHgFlaBkWzAZPeqezTCygmT1RYu/XAhVN0fhgGXOlZtqZhZcZEz+7VQDtVFiQbg4ysvPwSCOkIyYas0al2X2kxJ4gLxHT7JjVfjEUg1Lgo0JS+/fg3JKOKGXqtimhWDuwC+2gNFTzmvrjVJ+0vjiTXLc1JOGvgCdmBOGg+KKqnfBt8kV4XnFcSxPp3ySqG5gt5Rr5eDvIlYOtv1BhhunbIigFTQkVQQ7hgK9icq2DUpRrFiXPXiWKI2fG1BFdiVkTfg=='}

权限正常的情况检查下是否调用了沙箱环境下单，预支付ID是否为开通了APP支付商户号下单获取