1. Transmission error: During the transmission of the request message, the data packet may be lost, damaged or out of order, which makes it impossible for the receiver to correctly verify the SO. This may be caused by unstable network connection, network delay or other network problems.
2. Authentication algorithm mismatch: the authentication algorithm used by the receiver does not match the algorithm used by the SO in the request message, resulting in authentication failure. This may be because the encryption algorithm, hash algorithm or signature algorithm adopted by both parties are different.
3.SO expired or invalid: The SO in the request message may have expired or been marked as invalid, so it cannot be verified. This may be due to the expiration date of SO, being used by other requests, or being tampered with or forged.
4. Security policy restriction: The receiver can set a security policy, require stricter verification measures or refuse the verification of the request message. This may be caused by security policy requirements, access control rules or security risk assessment.
It should be noted that due to the influence of system, network environment, security policy and other factors, the specific reasons for the failure of so verification of request messages may be different. When solving the problem, we should carefully analyze the error information, check the relevant logs or debugging, find out the specific reasons and take corresponding measures to repair or improve.