I have one secure node that went down according to https://securenodes.eu.zensystem.io/nodes/73905/detail, but on the server no error weas found. zend is running fine, certificate is up, no problem to be found in any logs. However, a reboot / reconnect to the ZEN servers is required for the exception to close.
What can I do to prevent this in the future? Could the downtime be excluded?