Of course I changed it, but the client had to send the package
I poked the settings several times and re-saved in the order, and at some point the system made it possible to create a TTN (I suspect that perhaps at some point the NP API was not available)
Please don't do this again without approval.
You stupidly without any warnings took and created a new TTN-ku and the client stupidly could not send the package because of your actions, according to history, you can see that you overwrote the old (correct) new one
https://baza.cn.ua/admin/customorder/ order/28652/history/?filter2_key=valueold&filter2_type=search&filter2_value=&filter3_key=valuenew&filter3_type=search&filter3_value=&fieldkey=deliverynote&customfieldid=&filtercdatefrom=&filtercdateto=
I screenshotted the error, look in what cases such a ridiculous / non-informative error can be generated and correct it so that the error is understandable to the user
Also look at the logs (maybe something will happen)
https://baza.cn.ua/admin/logs/showall/ajax/?file=novaposhta-2020-11-27.log