IPhone message NEED YOUR

I have an iPhone 4. My boyfriend has a flip phone… (yes I know it's about an
antique now) and we have been texting for a while and this just accured, every time I try to text him it gets not delivered but I can still call him. This goes the same for all my other contacts with out iPhones. I NEED to keep in touch with him - he will be out of the country for a bit and i want to stay in contact. Also In my settings the imessage is on. But Does the same "not delivered" thong when imessage is also off. How can I get my phone to receive texts and send to non iPhone contacts? Is it somthing in my settings? And I need someone to direct me on what to do. Thank you my number is 774-994-0300 to reach me for questions Thank you!IPhone message NEED YOUR Help

Yes you need to restart the phone and it will start working again to restart it hold the home button and the power button down at the same time until the screen turns black then wait for it to turn back on