Help! Samsung native email app can't connect to comapny o365 account

[XNote9]

Hi there, 

Today I noticed that my Samsun Email App stopped syncing with company o365, so I did couple things to troubleshooting but no luck. 

1. I remove the accout and readd it.

    a. Sometimes it works, I can add it. And it downloads emails up to date. Then it stops syncing after couple minutes. 

    b. Most of time, it says Couldn't verify your account. And I can't add the emai account

2. I uninstall the update, same issue

3. I install the update back , same issue. 

4. I reset app data, same issue

5. I reset all phone setting, same issue

6. I clean up cache partition, same issue. 

7. I remove this phone from my o365 account, same issue. 

I finally install Outlook App, which works like a breeze. 

But I really like the native email app, can anyone please help me on this? BTW, I don't want to do a factory reset just for this. 

Thanks in advance. 

[DannyT]

Hi there, @XNote9.

Could you try removing the Outlook account and then re-adding it as an Microsoft Exchange account? You can do this by going to: Settings > Cloud & Accounts > Accounts > Add Accounts > Microsoft Exchange > Enter details. 

Let us know if you have more success with this. 

[XNote9]

I got this issue solved. It turned out to be a limit from Microsoft o365, here is the KB for it. 

https://support.microsoft.com/en-us/help/2748176/a-mobile-device-intermittently-can-t-connect-to-exc...

Basically, if you mobile device syncs too much in a short period with o365, o365 will block it for 30-60minutes. In my testing, it's around 50 mintues.  When I do the initial sync, I got blocked. Then I have to trun off syncing or change it to manually and wait for 50 mintues, then continue syncing. I've been blocked twice before I finished syncing 3 days emails. 

And this is only blocking mobile device if you are using native email app, Outlook app will not be blocked. 

Well,, new stuff every day. 

[mekaniko]

How were you able to solve this problem?

[TaziDevil]

So no fix aside from remove your services from 365? I pay to be able to sync my emails, if that's suddenly an issue then so is where my money is going!