Accessing the cloud not possible from Canary Island (Gomera)

I skip the introductory details because they are not relevant in my problem. At least thats what I believe.
I’m running a Nextcloud since the classical Nextbox. All works fine except when I call my Nextcloud from a holiday location on the Canary Island (Gomera). Then I receive a message that my certificate is not correct and all traffic to my cloud is stopped worldwide. This situation can only be rectified by renewing the certificate. This can only be done from home.
I know that this is not a Nextcloud problem. But it is a big problem and I have no idea what to do.
Is there anybody with an idea? (Aside off “spent your holiday at home”)

Would be nice if you posted the exact errormessage, where you get this message and all the other details you can provide. Are you using some wifi in a hotel? Maybe they try to fool you with different certificates. Did you try using mobile internet? Did you block other countries in your nextcloud serverconfig?

thank you for your interest.
There is no error message in nextcloud. And I don’t get any message.
I believe there is a firewall filter problem on the client’s side, filter is blocking names not IP and my name ( triggers this behaviour.
What I need is an idea to circumvent this. I have looked into bruteforcelogin and file access control but both apps do a kind of whitelisting. I want a blacklisting for just one (group?) of IPs.
My spanish is rather rudimentary and the interest in this exotic problem on the clients side is minimal I would like to solve this problem myselv. But I need an idea on how to do this.
Thank you

Then I receive a message that my certificate is not correct and all traffic to my cloud is stopped worldwide.

Can you please post this message in detail? Without I can just guess…

well yes, what I meant was the browser specific alarm about an invalid ssl certificate.

Alright. As your cert is valid the problem seems to be the clients browser or you tried from a network which is replacing the certs in a man-in-the-middle way. I asked you some questions before: Did you try from a hotel wifi or via mobile internet when you’ve been to la gomera?

this happens only from the hotel supplied wifi.
The problem is, that as soon as a connect is made my cloud in Germany dies and does not respond to any call.
And some of my equipment I carry around (phone + pad) native apps like calenders or contacts or mail are making connection without me interfering. And that always results in a dead cloud.
Thank you

It sounds like the hotel is intercepting SSL Traffic since the link you posted : has a valid certificate.

This page tells, that some older Apple devices tell a “Server sent fatal alert: handshake_failure”

Safari 6 / iOS 6.0.1 Server sent fatal alert: handshake_failure
Safari 7 / iOS 7.1 R Server sent fatal alert: handshake_failure
Safari 7 / OS X 10.9 R Server sent fatal alert: handshake_failure
Safari 8 / iOS 8.4 R Server sent fatal alert: handshake_failure
Safari 8 / OS X 10.10 R Server sent fatal alert: handshake_failure

High Mornsgrans
thanks very much for this interesting enlightment. But, I must admit, my understanding is very limited.
It is not yet a solution, but a light on the horizon and I it is a point to start arguing with my supplier.
Thank you very much indeed

Maybe you shouldn’t argue with anyone but update your devices and don’t use the shitty hotel wifi…

It is very easy:

  1. In the right column you will find the probable error message.
  2. Just compare your IOS/OSX- and Safari version with the list above.
  3. If your versions are in the list, you found the reason of the issue and need to upgrade Safari and IOS/OSX to a more recent one.

yes, you are right.
But unfortunately this are not my devices. They belong to the hotel.
Thank you