Connecting Problems?

Good Evening!

Some time ago I installed Nextcloud Server Version 10.0 on my webspace with all-inkl.com here in Germany.
I didn’t need much administrative work up to now.
Now I want to update the Nexcloud server on my web space and I got some problems in doing this:
(First of all, complete Backup done via ftp)

I am using my PC with win10.
Nextcloud:## PHP Version: 5.6.38
Nextcloud:## Database Type: mysql Version: 5.6.38
I tried firefox, edge, iridium browsers today to solve the following problem:

So I wanted to start the updater as administrator.
When doing this I get at first the following information:

Initializing

Current version is 9.1.0.16
No updates found online.

After rechecking I get the following information:

Initializing

Current version is 9.1.0.16
Can’t fetch feed.
cURL error 7: Failed to connect to updates.nextcloud.org port 443: Connection timed out

The Logging Protokoll

Protokoll

Info no app in context Invalidating tokens older than 2019-01-19T17:35:11+00:00 2019-01-20T17:35:11+00:00
Error PHP opendir(/tmp): failed to open dir: Permission denied at /www/htdocs/(my user name)/nextcloud/lib/private/TempManager.php#189 2019-01-20T17:35:11+00:00

When I try to open “Tips & Tricks” in the administration menu I don’t get a website connection.
So is my problem a connection problem?
Is it a problem of nextcloud, at the level of my webspace provider or a problem of my windows10.

As you may imagine I am not very advanced in using Nextcloud.
I would be grateful if there is anybody who could give me an advice.

Thank you in advance
peterg