The following operations are not recommended for customers. Please contact the service provider or Sangfor technical support to perform these operations. The operations may interrupt customers' business. However, if customers see the error (code: 0001-0004), it indicates that the SSL VPN service is abnormal and the business is already interrupted. In this case, performing the following operations will not cause other related issues.

Solution:

Run the 0001-0004_handle.sh script, then reinstall the pre-upgrade check package.