No relevant resource is found in the selected language.

This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies. Read our privacy policy>Search


To have a better experience, please upgrade your IE browser.


eLTE terminal attach fail - "unknown or missing APN"

Publication Date:  2019-01-14 Views:  730 Downloads:  0

Issue Description

Freshly commissioned test eLTE network will not accept terminals, which will continue displaying "no network".

In the user trace captured from the cloudUSN OMO we see "Attach reject" and "normal release".

Alarm Information

no alarms is issued nor on the eNodeB or the eCNS280

Handling Process

Looking further into the error messages in the user trace we find EMS_SIGNALING_ABNORMAL with uwProtocolCause: esm-cause-unknown-or-missing-apn(27) and udwInnerCause: usn-sm-upsel-apn-dns-target-qry-hostfile-fqdn-not-found(1357187173)

"FQDN" not found suggest a DNS query fail, we look furthet at "SM_DNS_REQ" and "DSN_SM_RSP" messages:

Find that from the 2 targets that are queried only one is successfully resolved:

Target 1 being: TAC-LB01.TAC-HB00.TAC.EPC.MNC060.MCC460.3GPPNETWORK.ORG - successful

and Target 2 being: ELTE.APN.EPC.MNC060.MCC460.3GPPNETWORK.ORG - failed

Root Cause

Finally we take a look back into the configuration script of the cloudUSN OMO to see if there is the line for target2 ( ELTE.APN.EPC.MNC060.MCC460.3GPPNETWORK.ORG) and actually it is missing:


What we've found instead in the configuration file was DNS entry for APN "" and not for the APN "eLTE" that was actually queried:


The APN has been customized, but not all the corresponding fields were updated in EasyGo V1.5.26:

The solution was to replace with elte in the following line: