Issue to connect to TTN3

Hello,

I have 2 different 433Mhz RAK devices , and I could not connect them to the new TTN3

In Rak7258, I see an error message [SYS:ERRO] Parsing of JSON failed - ‘station.conf’ ignored
I followed the instructions as at - Supported LoRa Network Servers | RAKwireless Documentation Center

In the RAK2243 , there is no option to connect to the TTN3 in the version on the website , is there any guide available ?

Hope someone can help with that here