Question I think I broke my DNS

[divepit]

Hello all,
I've been switching domain providers in the last two days and now I think I really messed up my DNS configuration.

So the main problem I'm currently trying to solve is, that when I visit my website from my University Network, I get the plesk default page for all of my domains. As soon as I switch to a network that is not related to my University, the website loads fine (at least one of them). The preview websites all work flawlessly. Even though on my phone it tells me that the website is insecure (https seems not to work on mobile now?) and it appears as secured on my laptop.

I hope this is not a duplicate but I ran out of things to google and couldn't find any solution. I'm not very familiar with DNS configuration so I assume I went wrong there. I'm running plesk onyx 17.8.11 on Debian 9.9.

Does anybody have an input as to how I could go about fixing this?

 

[Ales]

By switching domain providers, do you mean that you've switched registrars for the domain? You've transferred the domain from one registration provider to another? If that's all you did, then the DNS should not have been affected in any way.

I there anything else that you did, such as change the name servers for the domain(s) in question?

In any case, it will be very hard to provide advice without knowing the actual domain names.

 

[divepit]

By switching domain providers, do you mean that you've switched registrars for the domain? You've transferred the domain from one registration provider to another? If that's all you did, then the DNS should not have been affected in any way.

I there anything else that you did, such as change the name servers for the domain(s) in question?

In any case, it will be very hard to provide advice without knowing the actual domain names.

Thanks a lot for your answer! I did change registrar and then the new registrar asked for a nameserver. I provided them what I thought was the correct nameserver (ns1.mydomain.com) but that didn't seem to work so I reset the DNS and Nameserver settings to the registrar's default and just directed the A record and AAAA record of all the domains to my plesk server. As I hadn't realized that the site was only down within our uni network, I went into plesk and reset all the DNS settings to default and reconfigured the nameservers according to the provider's tutorial.

To be clear, the sites now function perfectly fine from any network except the uni network. From the uni network (where the site is most frequently used), the domains connect to the server but just show the plesk default page that says there is no site on that domain. The reason why I was messing around with the DNS in the first place was because I was switching in and out of the uni network which made me go crazy as the site went up and down randomly until I realized it was because of the network..

I was able to resolve the SSL issue as that was a mistake in the hosting settings. I'm just a little confused as to what could cause the site to fail only specifically from one network. A friend suggested as the website is used very frequently by the students at our uni, "the DNS Proxy might have cached the site and it will solve itself in a few days" so I'll go on and read about DNS chaching as I'm not really sure how that works..