External Mail stopped Flowing

Exchange 2013 SP1 with 2 member DAG. Internal email works fine but external email does not work at all (sending or receiving). This happened last time the server was updated with windows updates and exchange updates. First, the windows updates were done. Then put into maintenance mode and exchange updates were done. Reboot and all the services start and everything appears fine but no external email. Last time i remember something about queue poisoning. Nothing in the queues. Here is something from the log:

2015-09-26T21:26:25.864Z,08D2C3BEDC4692AD,SMTP,shadowredundancy,+,ShadowRedundancy 00000000-0000-0000-0000-000000000000;QueueLength=<no priority counts>
2015-09-26T21:26:25.864Z,08D2C3BEDC4692AD,SMTP,shadowredundancy,>,dagmember1.domain.com[192.168.123.9]
2015-09-26T21:26:26.895Z,08D2C3BEDC4692AD,SMTP,shadowredundancy,>,Failed connection to 192.168.123.9:2525 (ConnectionRefused:0000274D)[TargetHost:dagmember1.domain.com:2525|MarkedUnhealthy|FailureCount:1|NextRetryTime:2015-09-26T21:27:26.895Z][TargetIPAddress:192.168.123.9:2525|MarkedUnhealthy|FailureCount:1|NextRetryTime:2015-09-26T21:27:26.895Z]
2015-09-26T21:26:26.895Z,08D2C3BEDC4692AD,SMTP,shadowredundancy,-,Messages: 0 Bytes: 0 (Retry : Unable to connect)
2015-09-26T21:26:26.911Z,08D2C3BEDC4692AE,SMTP,mailbox database,+,SmtpDeliveryToMailbox b167e9f8-98a2-4635-a6da-17cc153dadc8;QueueLength=TQ=1;RN=1;
2015-09-26T21:26:26.911Z,08D2C3BEDC4692AE,SMTP,mailbox database,>,dagmember0.domain.com[192.168.123.12]
2015-09-26T21:26:26.911Z,08D2C3BEDC4692AE,SMTP,mailbox database,>,Established connection to 192.168.123.12
2015-09-26T21:26:27.005Z,08D2C3BEDC4692AE,SMTP,mailbox database,-,Messages: 1 Bytes: 28431 ()

Both servers are accessible. I have restarted the transport service and i can send a couple external emails but it soon reverts back to getting/sending no email externally. Here is the first event log from dagmember1:

Scenario: ProcessKillBit. Failed to read killbit list file because of exception System.IO.IOException: The process cannot access the file 'C:\Program Files\Microsoft\Exchange Server\V15\ClientAccess\owa\prem\15.0.847.41\ext\killbit\killbit.xml' because it is being used by another process.
   at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
   at System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy, Boolean useLongPath, Boolean checkHost)
   at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, FileOptions options, String msgPath, Boolean bFromProxy)
   at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share)
   at Microsoft.Exchange.Data.ApplicationLogic.Extension.KillBitHelper.TryReadKillBitFile(Int32& refreshRate, DateTime& lastModifiedTime)

Renamed the queue folder and started transport service back->same issue. Restarted both dag servers->same issue. What is the best way to troubleshoot this issue?