openSUSE admin

Hello,

I would like to inform you about an update issue (?) in which I ran into
for the last 3 days:

I was trying to update OpenSUSE Leap 15.4 on my laptop the "regular way"
(by running "PackageKit" from the GUI and finally "zypper up" on the
command line). To my surprise, both methods failed several times, as the
entire update process got stuck and didn't ever finish.

My final workaround was to temporarily change the urls of the software
repositories from "http://download.opensuse.org" to
"https://mirrorcache-eu.opensuse.org". After that, the update on my
laptop was successful.

Strangely enough, this issue only occured on my laptop. Any other PC in
my household apparently can be updated without any changes to the repo urls.

May I ask you the following questions:

a) Could you please provide me with some details about the possible
cause of this "error"? Is it possibly related to my private LAN
configuration (firewall, router etc.) or is it more likely to be caused
by a misconfigured mirror server?

b) Is it generally safe to change the repo-urls in the way described
above - or does this impose a security risk to my system?

Best regards
Winfried Hubbe (Germany)