1, WPS did not correctly identify the electronic signature: WPS did not correctly identify the electronic signature format used by Fuxin, which made it impossible to verify the validity of the electronic signature.
2. Expiration of electronic signature certificate: the validity period of electronic signature certificate is limited, and the certificate has expired, so the electronic signature will be invalid.
3. The electronic signature certificate is not credible: WPS doesn't trust the electronic signature certificate used in reply, so it can't verify the validity of the electronic signature.