Hi Lan,
The issue could be related to various causes. To solve it, please try the steps below:
- Re run the HCW (Hybrid Configuration Wizard) to configure the connector and try again.
- Check if there are any firewall settings or antivirus products blocking the communication.
- Try removing the connector, then create a new one using TLS encryption.
For more details, please refer to: Understanding Transport Layer Security (TLS) in FOPE.