Vodacom South Africa 3G data connection, is blocking Blynk-cloud (PSH flagged) TCP/IP login binary-payload packets when my NodeMCU attempts to connect via WIFI tethered smartphone.
I have no Idea why they would block/drop these, all other types of data such as HTTP, MQTT seems to pass through without issue.
After extensive testing and searching around, I tested using a SIM card from a IOT sim card provider based in Germany which issues global data-roaming sim card for M2M/IOT applications.
I have yet to test the other South African cellular providers (MTN, Cell C etc).
I did request an unrestricted APN from Vodacom SA, and they send me confirmation of that and I changed the APN settings as directed.
I would be very interested to hear from anyone else who has experienced this issue from GPRS/3G/LTE providers around the world.
Confirmed: no issue with Blynk-cloud or Blynk for ESP.
Thanks Bylnk for an excellent contribution to IOT.
Thanks Gunner and Pete Knight for your insights.