using UDP fails when binary is compiled with Online compiler but if I compiled with CLI GCC_ARM then UDP works.

Bug

Version information
mbed-os-example-client, revision 9468fd3, tag mbed-os-5.7.0-oob

Environment details
https://os.mbed.com/compiler

Expected Behavior
Registered object successfully!

Actual Behavior
Starting mbed Client example
[EasyConnect] IPv4 mode
[EasyConnect] Using WiFi (ESP8266)
[EasyConnect] Connecting to WiFi Anfield-tower
[EasyConnect] Connected to Network successfully
[EasyConnect] MAC address 5c:cf:7f:04:6a:f2
[EasyConnect] IP address 192.168.43.142

SOCKET_MODE : UDP
Connecting to coap://api.connector.mbed.com:5684
handle_timer_tick, device not registered

Steps to Reproduce

1. compile using TCP => restart K64F
   Starting mbed Client example
   [EasyConnect] IPv4 mode
   [EasyConnect] Using WiFi (ESP8266)
   [EasyConnect] Connecting to WiFi Anfield-tower
   [EasyConnect] Connected to Network successfully
   [EasyConnect] MAC address 5c:cf:7f:04:6a:f2
   [EasyConnect] IP address 192.168.43.142

SOCKET_MODE : TCP
Connecting to coap://api.connector.mbed.com:5684

Registered object successfully!
handle_timer_click, new value of counter is 1

2. change to UDP
   replace "M2MInterface::BindingMode SOCKET_MODE = M2MInterface::TCP;" with
   "M2MInterface::BindingMode SOCKET_MODE = M2MInterface::UDP;" in simpleclient.h

3. compile using UDP => restart K64F
   Starting mbed Client example
   [EasyConnect] IPv4 mode
   [EasyConnect] Using WiFi (ESP8266)
   [EasyConnect] Connecting to WiFi Anfield-tower
   [EasyConnect] Connected to Network successfully
   [EasyConnect] MAC address 5c:cf:7f:04:6a:f2
   [EasyConnect] IP address 192.168.43.142

SOCKET_MODE : UDP
Connecting to coap://api.connector.mbed.com:5684
handle_timer_tick, device not registered

Enhancement

Reason to enhance/problem with existing solution

Suggested enhancement

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Cons

Question

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