I‘ve checked the log, unfortanely notthing that could help.
openhab is running on a raspi 3b+ with a 128GB Samsung SSD.
Raspi is connected via LAN to a switch (which works fine) and the switch is connected to a FritzBox.
Alexa Skill works fine when raspi is rebooted, but unfortanely only a few days.
I think you “only” have issues with the cloud connector and because of that Alexa is not working.
Try setting the cloud connector to debug to check if anything helpful is in the logs.
Therefore, access Karaf and do the following
log:set DEBUG org.openhab.io.openhabcloud
Until the next reboot, the cloud connector will generate debug logs
Restart your Openhab cloud bundle in Karaf. Do bundle:list find out what number your OH cloud is and then do bundle:restart 215 (replace with actual bundle list number)
An alternative approach is to use the Hue emulation binding.
Alexa is able to find Hue bridges locally and talk to them directly without any Internet involved except the voice recognition: In my experience it is way faster this way.