Problem description
The MSE instance is inaccessible from the public IP address of your application.
Possible causes
The IP address whitelist of the MSE instance does not contain the public IP address of your application.
The public IP address of your application has changed.
Solutions
Check whether the public IP address is included in the IP address whitelist of the MSE instance. If the public IP address is not included, configure a public IP address whitelist by following the instructions provided in Configure a public IP address whitelist.
Check whether the public IP address of the application has changed.