Microsoft Windows Server 2012 R2 with all the updates
Microsoft Exchange 2016 (Build 225.42 which is RTM)
Issue: ActiveSync isn't working for anyone on any mobile platform, whether it's Android, iOS, Blackberry 10, etc. No useful error message, just the generic "Unable to verify account information" with iOS and similar messages on other platforms.
- server's been in production for 2 weeks and is sending / receiving just fine as an authoritative host and receives two forwarded external relays
- webmail works fine internally and externally (on the internet, from home) no issues
- I have not yet purchased a certificate for this site but that shouldn't be an issue since other sites are functioning fine without
- Can't run through the ActiveSync test Microsoft offers as it fails to get past the certificate issue. I fired the test at a number of other sites without certificates that are happily working fine with hundreds of phone and tablet ActiveSync users and it fails there too. Even if you select the 'ignore' option on the test site, it still craps out.
- Checking IIS logs shows the users 404'ing with external addresses (I sanitized the name and address):
2015-10-20 15:35:02 192.168.0.2 OPTIONS /Microsoft-Server-ActiveSync/default.eas &CorrelationID=<empty>;&ClientId=AA1B5FOPF0CD8FPRGPX2RW&cafeReqId=ddb352-cc1f-4323-914d-247e0be1a862; 443 realdomain.com\johnsmith 157.56.75.164 Apple-iPad2C1/1102.55400001 - 404 0 0 43
There's piles of these for every test on every platform. The errors all end with 404 0 0 followed by a different number (hundreds of lines of this). Clearly they're getting in from the internet but they're... 404'ing.
- I see people asking what happens when you attempt to https://realdomain.com/autodiscover/autodiscover.xml and it asks for username and password, then provides error code 600 with invalid request, which is the same I see with the sites that are working fine.
- I ran through all IIS authentication settings and they're all set to appropriate defaults, compared with a functioning site.
I'm pulling my hair out here since this is the second Exchange 2016 install I've done and the first is working fine. There's one minor difference between this site and the other site in that this site is hosting an internal web application so other people have had their hands in IIS, but evaluating all sorts of settings doesn't show anything out of the ordinary.
Any guidance would be appreciated!