Using a hardcoded SF11 or SF12 is not allowed, as it takes a lot of airtime, increasing the chance for collisions with other users of the network. See Limitations: data rate, packet size, 30 seconds uplink and 10 messages downlink per day Fair Access Policy.
So try to lower that by trying SF10, SF9, SF8, …
Also, you won’t get a confirmation unless you use “conformed downlinks”, which you should use very sparsely (if at all) as explained in the same link.
Next steps:
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Re-generate your secret keys, as you’ve exposed them in your first post. Go into the device settings, and click the generate icon for both secret keys:
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While at that settings page, for testing you might also want to disable:
See ABP node stopped working -> Fixed by creating new ABP.. Why? :)
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Change the text format into a proper 2 byte number; Best practices to limit application payloads.
Enjoy!