Getting 2400 error in outlook application

I only had a problem with ONE of the outlook accounts. The free one. (other is attached to 365)

Error 2400 - So, I have the same problem. I have two outlook/hotmail accounts, one attached to 365 and one is free. The free one isn't working anymore.

I m not ready to do all this reinstalling and registry stuff, cause its so much wasted time. Instead, I would prefer, that Microsoft is getting their sh*t together and make an update for that. This thread is long enough, that several people have that problem. And thats only the people, who made a post to this topic. I pretty sure MS broke something with the last update and now a lot of people with this account constellation have that problem.

This worked for me!

Brilliant

Just switching back and forth between accounts (I have 2 Exchange accounts) fixed it in 2 seconds.

Also had the dreaded Error 2400 message with Outlook. None of the suggestions listed on here worked. Spent 2 hours with Microsoft remotely working on my computer & assistant could not fix it. Eventually all she could do was a workaround, creating a new profile on my PC & setting up a fresh version of Outlook on it. Works fine now, but a bit of a pain migrating everything else to the new profile. And, coincidentally or not, it all started after a windows update!

Katherine,

There is a service incident that is causing Outlook Web Access not to work, EX610644. You can track status on Twitter here, Microsoft 365 Status on Twitter: "We're investigating an Outlook for the web access issue affecting our customers in North America. Please refer to the Service Health Dashboard in the admin center under EX610644 for more details." / Twitter.

How can I sign into hotmail after receiving this message?