Oracle API Gateway Node installation error on join action

I am trying to install a gateway node setup using a OCI-classic. Though i could complete the action install,configure & start in sequence, i am unable to finish the JOIN action. I am doing the steps in sequence. Below is the snip of the logs that i have got from registerNode.log (full logs attached as a image): 

DEBUG:root:Performing dev env SSL related workarounds
ERROR:root:Error: Unable to add grant , reason = ['Traceback (most recent call last):\n', '  File "APIGateway.py", line 2246, in addGrantToUser\n    resp = urllib2.urlopen(request,data = addGrantJson,context=sslContext)\n', '  File "urllib2.py", line 154, in urlopen\n', '  File "urllib2.py", line 429, in open\n', '  File "urllib2.py", line 447, in _open\n', '  File "urllib2.py", line 407, in _call_chain\n', '  File "urllib2.py", line 1241, in https_open\n', '  File "urllib2.py", line 1201, in do_open\n', '  File "httplib.py", line 1121, in getresponse\n', '  File "httplib.py", line 438, in begin\n', '  File "httplib.py", line 402, in _read_status\n', "BadStatusLine: ''\n"]
WARNING:root:Gateway runtime user could not be given the requisite node service account grants
INFO:status:complete action: join isSuccess: failed detail: {"status": "NOT_JOINED"}
ERROR:main:Action join has failed. Detail: {"status": "NOT_JOINED"}
INFO:main:Gateway join complete.Status = NOT_JOINED.Please check log files for more details

I am pretty sure that i have the entered Gateway runtime user in the node service account grants of the logical gateway itself.

The gatewayExecutionMode is Development. And, i have checked the status of the gateway node but it looks alright. I have attached the logs as image.  I doubt this is related to network. But, could someone please give me a clarity on this ? 

Solution : 
Check your MTU setting for the network interface of the gateway node machine. It should be 1500. For more details, how to set the MTU to 1500 (http://www.linuxblackmagic.com/search/label/MTU)