Reason: SPF check failed.
Suggestion: SPF is set for the sending domain, but the check failed. If there is a new IP, please update the SPF record in time.
To minimize the uncontrollable impact of DNS query failures on incoming emails, Tencent Exmail will cache DNS records for no more than 12 hours. For an IP change, please update the SPF record in advance.
For details, refer to: https://open.work.weixin.qq.com/help2/pc/19817?person_id=1