BB10 Exchange ActiveSync Issue?

I have 6 Z10's, 4 IPhones and 1 Android on my network using Activesync for email to an Exchange 2010 server(Version 14.2). The 6 Z10's are having trouble forwarding and replying to some emails. They will show in draft after sending or the red circle with a white line in the middle. I started testing sending emails with attachments and I can�t seem to send an email with an attachment larger than 256KB. I setup a Google Apps account using Activesync on my BB10 phone and it sends larger attachments perfectly.
When an IPhone or Android phone sends large attachment emails using the same server they will send fine.
I am pretty stumped on this one right now. Does anyone have any insight?

Mine got 2 corporate emails on activesync, mails, calendars all work perfectly. The only problem is part of my contacts non sync. Never had any problems sending or receiving emails.

Posted via CB10

I'm having the same problems. Also updated to the latest OS(10.0.10.85) on the Z10.
I get error: "Acknowledgment for send was not received from Server"

I don't get an error. The email will just show a Draft icon and never send. I am still working on this issue.

Posted via CB10

I had some issues recently with an Exchange server that I manage where the ssl certs were not set up right and some strange things resulted. So maybe you can look into ssl?

Posted via CB10

All our certs look ok. I have tested active sync with:
https://www.testexchangeconnectivity.com/ and everything passed.

I have an open ticket with Blackberry on this issue.

Found a partial fix. I used the internal address of a secondary hub cas server. Now I can send out. Seeing this error in the active sync logs:
+Budget>>Conn:1,HangingConn:0,AD:18000/18000/0%,CAS:90000/89862/1%,AB:18000/18000/0%,RPC:90000/89940/1%,FC:1000/0,Policy:DefaultThrottl

Found the fix for this issue. In the Exchange EMC go to CAS active sync settings. Then "Authentication" tab. Then ensure "Ignore client certificates" is selected. Also I deleted all old expired unused certificates. That was the only difference on the 2 CAS servers.

Turning on "ignore client certificates" works indeed, thanks!