Q: My new IPad Air 2 will not let me send text messages to non Apple devices.  What can I do to fix this problem?

An iPad is not capable of natively sending an SMS or MMS messages.  Those services require a cellular voice channel connection, and a data tablet is only capable of a cellular data channel connection, not a voice channel connection.

If you have an iPhone, under the settings on the iPhone you can enable forwarding with your iPad - where the iPhone actually sends and receives the SMS texts and shares them with your iPad.

Otherwise, you will need to use an app and internet service like the telegram messaging app. Or you can send emails to the persons cell phone via their carriers texting gateway (e.g. 1234567890@txt.att.net if they use AT&T in the USA).

iMessages between iOS apps are separate from SMS texts as iMessages use Apples internet service and equipment. But the SMS protocol crams a short text message into the residual bandwidth of a cellular phones voice channel and cannot be sent over a cellular data connection.

the gsm module is data only so you can't send normal sms's between ios devices it's not sms really it's iMessages which is pretty much IM chat

there are sites and maybe apps in app store which use online sms services you can use