Problems sending sms

Hello

I recently joined Meo and I am using an e-sim for my mobile service. 
 

I went to send an SMS yesterday from my Portuguese number, but it won’t let me. 
 

I don’t get any error message, it literally just doesn’t let me send. (It’s an i-message and the blue “send” arrow is there but when I hit it, nothing happens). 
 

Can anyone help?

thank you