Lwm2m Client example unable to read/write/observe from server

[YuguoWH]

Issue Summary

• Type: Bug
• Category: Example
• Priority: Urgent
• Release Version: 2019.06

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Bug

Development Environment

• HOST OS
  Input the host os name and its version.
  For example, Windows 7, 64Bit | Debian Linux 8.6, 64Bit

• TOOLCHAIN
  MWDT & GCC

• BOARD
  EMSK

• ARC CORE
  ALL

Bug Description

After successful connect to leshan server, any operation from leshan webpage would trigger exception, unable to read/write/observe.

Tested with release version 2019.06-RC1 and 2018.12
Tested with two leshan version, unable to find version number, identify with download date:
Late version leshan: downloaded at 20190812
Old version leshan: downloaded at 20171110
Test result in table:

Release	Latest leshan	Old leshan
2019.06-RC1	exception	exception
2018.12	exception	success