Password-protected file downloads are configured to be allowed. However you get ICAP error after files are downloaded through the Web Security Service (WSS) because the files are sent over ICAP to be scanned.
ICAP Error
An error occurred while performing an ICAP operation: "File is password protected"
Tech support information: icap_error
Web Security Service
Malware scanning often rejects password-protected archives, causing an ICAP error to occur during the attempt to download.
WSS allows exemption to specific file types from ICAP errors by allowing them to be sent to the client.
Steps to add Password Protected Archives to scanning exemptions.
3. Scroll down to Scanning Error Handling and click the Add Scanning Error Exemption button.
4. Create a Scanning exemption:
5. Go to Add Error Type Conditions and select the Add Password Protected Archives option.
6. Click Save and Activate.