Officejet Pro X476dn Scan to Email - Error

[RII]

We have several of the x476dn machines and when scanning to email, the scan will complete and be sent to the recepient. 

Before the job completes on the front panel, we receive an error message:   "Network Connection Error. Check network and try again."

After the scanned paper travels through the ADF, it will appear in the user mailbox within 10-15 seconds.  The display still shows a processing screen and then about 60-80 seconds later, we receive the error message.

Settings for the devices as follows:

Only connected to network interface, no USB.

IPv4 address issued from DHCP reservation so the machine keeps same address.

Email server properly configured to receive email (as evidenced by our ability to receive the scan in spite of the error)

Firmware version: LNP1CN1548AR

Any help is greatly appreciated, we do a ton of scanning and users have to wait for the error message before starting a new scan job.

-richard

[RII · Accepted solution]

Update - turns out for some random reason, the acknowledgement on our receive connector from the Exchange server was causing an issue.

https://technet.microsoft.com/en-us/library/dd351046(EXCHG.140).aspx#MaxAckDelay

We adjusted the delay to a shorter time and have so far not experienced any further issues.

Hopefully someone else can benefit!

-r