Troubleshooting an Invalid header value detected Error during Email Importting
After applying the 8.0.0 update, administrators may begin to receive POP3 Connection Error reports with the following detail:
Invalid header value detected
This is caused by the mailbox containing an email with non-RFC-compliant headers, which prevents the import process for completing successfully.
Please apply the 8.0.1 Maintenance Release via the Utilities > Update WHMCS page.