PC5250 Connection Error MSGPROG706

Making a Client Access connection over TCP/IP, PC5250 may report a Program Check 706 (PROG 706) error. The text of this message is, An SNA message was received with incorrect chaining.

This usually indicates a network issue. Check the average time for a PING. Also, try the following:
ping -l 1000 [AS/400name]

This will PING the AS/400 system with 1000 bytes of data rather than the 10 bytes of a regular PING. This may yield a very high average time, or it may time out. In this case, the network is most likely loosing frames. A lost frame will result in a TCP protocol error.

Theoretically, protocol errors should not be reported to the PC5250 application, but in this case they might. The error text indicates an SNA error because the PROG message text was written prior to SNA connectivity for this product. The PC5250 interprets a missing frame as an SNA chaining error.