Microsoft 365 email issue after DNS change

[Dogg Thang]

Any of you nerds know about Microsoft 365? Yesterday, I had to change my DNS thingies on my web domain due to a server shift with my hosting people. For the last few years, our email has gone through Microsoft 365. The DNS shift has knocked out my email... kind of. I seem to be able to send email but not receive it. But what’s odd is that my wife’s email on the same system doesn’t seem to have been affected.

I didn’t set up 365 when we got it so I don’t know anything about it and going in yesterday to take a look, well, it looks odd with MX things and TXT things that don’t look familiar. But there is some sort of auto discovery thing on which implied to me that it might be able to sort out DNS shifts itself.

But given my wife’s email seems to be working, should I just wait longer and see if it sorts itself out? Could it just be a slow DNS change issue?

Edit: in attempting to fix this, I seem to have broken everything. If the internet vanishes today, you'll know why. Everything is broken. My website has vanished. It's hard to put into words how much I hate computers and IT issues.

[MartyG]

It can take some time for DNS changes to propagate through, but I'm not really clear on what you changed.

The MX records tells email which SMTP email server it needs to route to, but if you're using office 365 as your email provider, I'd be surprised if you needed to change the MX record at all, as I'd have thought it would have been pointing to the office 365 email server which you'd pick your email up from (and it's probably sending to that from your client, which is why that's still working)

MX routing is separate to your web routing (your A Name record), TXT records are something else again often used to provide additional information about your domain.

Do you have a note of what the DNS record was before you started changing it?

[Dogg Thang]

Thanks Marty. Yeah, it might just take more time. I’ll have a note somewhere of what the DNS was before I changed it, yes. I don’t know how Office 365 works to be honest but it does look like it points to an Office server rather than anywhere on the original domain but there is a domain section in the admin bit given me error messages about those MX and TXT things warning me that it could affect email. But maybe that will just sort itself when the DNS has propagated. I’ll see how it is tomorrow before trying to mess with anything more. I made an awful mess today with some other stuff!

[MartyG]

Propogation normally takes a couple of hours for the main root servers, but can take longer to get everywhere.

Office 365 is just a catch-all for Microsoft's Office product - depending on the license gives you web only apps or web and local apps. The mail servers don't care whether you're accessing your mail box from the web or the app, the config will simply be pointing it to the MS Exchange box.

The MX record is for the incoming email, it just points the text domain name address to the IP address of the SMTP server (or Web Server for A Name records) - that's basically all DNS is, a service that transforms more human friendly text into IP addresses. I've just checked my work MX record for our main domain (we use 365) and it is indeed pointing to MS's email service, so you probably didn't need to change it.

The TXT record isn't an absolute requirement for a domain to work, but sometimes they're used as an easy way to authenticate domain ownership when you're setting services with a provider. Given you've already authenticated ownership previously, you shouldn't need to change this. It doesn't route anything, it's just a text file that's presented when requested.

[Dogg Thang]

Looks like it might be in the process of fixing itself. A couple of mails got through overnight but not all (I can check what's coming in via cpanel of my website) although the admin panel of 365 still throws up all those warnings.