The issue is caused by an Active Update certificate being expired. If the ScanMail is lower than Patch 5, the recommended solution is to upgrade it to the latest patch. This ensures that the certificate is renewed and Active Update works properly.
It is advisable to check the version of ScanMail being used and upgrade it to Patch 5 and later versions. Additionally, customers are advised to check the following:
- Allow *.trendmicro.com/* on their Firewall/Proxy to ensure that components can be downloaded successfully.
- If their Proxy or Firewall is performing HTTPS decryption, try to bypass Trend Micro URL to see if it is the one causing the issue.