Exchange User on OWA unable to get Autocomplete Working

We have a cloudbased exchange server, and 2 users (so far) who I can't seem to get autocomplete working for them again on the OWA site in a browser.

I've isolated the issue to possibly the exchange server having a hiccup but would like to hear some input and things I might not have tried yet to resolve it. Here's the things I've found out and tried:

1. It is only happening to a few mailboxes.
2. The autocomplete was working for them before and failed around noon for them.
3. Using the "Open another Mailbox" option to open another mailbox, and that mailbox will have working autocomplete, but not on the original mailbox.
4. It follows the mailbox no matter the browser, computer, or network. The problematic mailbox is still a problem with any combination of these, and working mailboxes are fine on the ame network, browser, and computer.
5. Cache Clearing does nothing.
6. I cleared the cookies too.
7. Incognito/InPirvate does nothing.
8. I tried deleting the ilk.exe thing on the local computer in appdata. Nothing.
9. Autocomplete works in classic Outlook (they do not have a license for new Outlook).
10. Suggested People in the mailbox settings is turned off. But clicking on the "Activate Expanded Contact Suggestions" has no reaction from the browser or webpage.
11. I opened the console window in the browser and when I click on the Activate Expanded Contact Suggestions again, I see a POST error request giving a code 503 with "Service Unavailable" in parenthesis.
12. There appears to be no service issues related to user searching when I checked the service health site on out microsoft dashboard.
13. Adding a new contact into the People tab within the problematic mailbox does not show up in autocomplete either.
14. Searching for people in the Peoples tab does work (No where else).
15. Manually typing in the email address name (should the user know it) works.
16. The "To:" button also works.

I have found this thread of a user having a similar issue however they have not replied back: https://learn.microsoft.com/en-us/answers/questions/5566214/auto-complete-not-working-while-searching-user-in

And tried the fixes in the listed article: https://learn.microsoft.com/en-us/troubleshoot/exchange/email-alias/address-not-autocompleted-or-suggested

The two workarounds in the article, adding the address manually into the contacts/people tab, and removing address book policy (there is none), do not work.

Any insight is appreciated

Ron