emails are bouncing back when sending to yahoo

Just make sure you do a health check on office 365 for the domain. Mine was flagging issues, followed someone else's fix on here and it reset everything. All DNS data lost, errors flagged up and what was strange is 90% of them was correct when comparing to my CDN DNS with Cloudflare.

If you are hosting your DNS records outside of Microsoft 365 and using your Host or a CDN, remove your domain and reconnect it. That way you will see a new set of records that should be applied to your Host. Because I use Cloudflare (Which I recommend to anyone for security etc), Microsoft automatically communicate with their services and removed old data and replaced it with the correct/new data when adding the domain back in.

Then from there I went to my host and matched Cloudflare's CDN records like for like, removing any old that might have transferred from an old host. Refreshed my records in Microsoft and everything is now showing as green. Not sure if this as fixed the Yahoo issue going forward but I know my records are all good both ways.

Just to add if you are not using Microsoft as a DNS record for your domain and just for emails you don't need to worry about A records for I.P addresses that point to your host. This is only required if you are using emails from your hosting provider and not Microsoft. Do correct me on this?

Either way it looks to be working fine for now. Haven't had anyone in the office shout at me yet for not receiving any emails. Time will tell.

You SCREAM AT EVERYONE not to follow anyone's suggestions on this discussion and now you're giving suggestions. Interesting.

>> Mine was flagging issues, followed someone else's fix on here and it reset everything. All DNS data lost

Not sure what exactly you did but changing 1 record should never reset everything. Something is wrong with your DNS hosting company or you did something wrong. You're right about 1 thing, 1 person's problem and fix does not apply to everyone.

I totally understand and my experience just made me want to make others aware not to follow without first investigating.

I made the mistake of changing something first, and it reset my DNS records in 365 not my host. I got the "setup your domain tutorial" just by clicking the "Fix My DNS" tab next to the "Manage DNS" one which only shows if warnings/errors are present. Then to my surprise all records had "Error" next to them and lost all my custom A records and all hell let loose.

I was only shouting because I just assumed and didn't investigate. I was only sharing my experience and don't just assume the Fix my DNS tab will fix the issue. Just be careful. I have three layers of DNS records and one effected the other. It can be as simple as that. For me it was a case of removing the domain again and adding it back in and asking to sync with Cloudflare. This might not work for others who don't have a similar setup and wouldn't expect them to try it if not.

At the moment everything is showing as green on 365. All other DNS records on our CDN/Host are like for like (with additional A records). I am not keeping my hopes up to something breaking over the weekend. Microsoft have a reputation to just changing things and not pre-warning you. Then again I don't even think this has resolved the Yahoo issue and chose not to mess again until we get new un-deliverable's from these domains.

>> it reset my DNS records in 365 not my host.

Thanks for clearing that up.

Well:

I have not had the time to get a ticket with Microsoft yet as I only have 2 customers with Yahoo email and on the onset of this problem, I contacted my web and email hosting company and what ever the tech guy did, I can actually log into the mail server and send out email from my email address to my Yahoo customer and they received them.

I cannot use my office 365 outlook to send email to my Yahoo customer, not from my phone app nor my desk top outlook mail.

This truly is a Microsoft issue and with a company that size and so many subscribers paying so much money each month, I am surprised the Microsoft did fix the issues... if a Microsoft moderator is actually reading this, you guys should do something and treat your customer nicer, we are paying customers either by the month or annually and this is a big part of Microsoft business.