meteohub.de

It turns off at nightfall and reboots every morning, so that is not it.

Please debug on your side, why SSH remote tunnel cannot be established. There is nothing I can do from here.
As you share no information about router, provider, if it is a company LAN with packet inspecting firewalls, proxies, etc, I don't even have a clue what might block this in your environment.

I am using a TL-MR3030 flashed with Meteobridge, presently not using a memory stick, so it downloads on each bootup. It is connected to another TL-MR3020 which acts as a router with a 3G/4G modem dongle. This allows connection to the internet by mobile phone carrier, since the station is mounted in a remote area. The 3G dongle does not allow for port forwarding, hence the need for the tunneling. The tunneling worked most of the time until a week or two ago. It has not worked since. I have accessed it and rebooted it remotely several times in the past. Thanks for your help and suggetions.

for sure your 3G/4G provider. Check yourself and plug the Meteodrige into
a proper LAN/WLAN with a non-mobile provider behind and watch it working

As there is no "proper" connection with several kilometers, it does not really matter what the reason. I do not know what has changed, since it worked until recently, but I guess I will have to take a computer to the unit and make my changes manually. It is 1500km away from me and I will get there next spring.

can you please send the URL link you use for remote access to "info(at)meteobridge.com"?