Forum Discussion
Outlook on smartphone issue
We're having an issue with outlook APP for Iphone and android as well.
Exchange servers are NOT exposed to internet for OWA or Activesync services, they're only internally accessible.
The environment is made of 2 Exchange 2010 servers, in DAG, which are being migrated to Exchange 2016.
At the moment users are using built-in mail app on both Iphone or android to connecto to exchange 2010.
We started migrating users mailboxes from 2010 to 2016 without issue.
Outlook client on PC we're correctly redirected to exchange 2016 automatically.
The Built-in App on either Iphone or Android is able to connect to exchange 2016.
Now we'd like to switch from builtin mail APP to outlook APP for smartphone.
The problem is that Outlook is not able to connect to exchange 2016 server even if configured exactly as the built-in app.
The Error is as simple as "cannot connect to server"
Any idea of what the problem might be ?
- Yes, it's correct, you always have to point to the autodiscover on the On Prem server. In fact, Outlook for mobile uses Microsoft servers to resolve client autodiscovery. It is not the mobile which makes the discovery.
7 Replies
You need to open the IP from Microsoft to your On Perm Exchange server for accept connection with Outlook for mobile.
IP List :
https://learn.microsoft.com/en-us/microsoft-365/enterprise/urls-and-ip-address-ranges?view=o365-worldwide
When you can confirm the connection with https://testconnectivity.microsoft.com/tests/Eas/input you can use Outlook.
Outlook for mobile does not connect directly to the On Perm Exchange server but from a Microsoft server, this proxy connection is supposed to come from a geographically close Microsoft server.
- Hello Thierry,
So you are confirming the Outlook for IOS DOES require external connectivity, even if the activesync url should be resolved with internal server IP ?
The customer has a specific configuration in which the Smartphone APN is allowing the devices to be directly connected to internal network and resolve fqdn from internal DNS.
Is there a KB or microsoft article I can look at and share with the customer ?
thanksYes exactly. Because Outlook goes through Microsoft servers to query autodiscover. This does not depend on Active Sync. Other applications like Mail, Android Mail which use their own autodiscovery questioning system allow you to connect with ActiveSync without problem, which is not the case with Outlook for Mobile.
- Outlook mobile is, I think, connected to the on-prem Exchange through Microsoft cloud. So you have to open connection from MS IP addresses to your on-prem exchange servers.
See https://learn.microsoft.com/en-us/exchange/clients/outlook-for-ios-and-android/use-hybrid-modern-auth?view=exchserver-2019- Hello Feller,
the article is about a hybrid configuration we're in a purely on-premises environment.
I'm not sure it could be the issue.
thanks
