I also have the unlocked s7 edge purchased from Samsung 4/10/2017 with the exact same issue. I use Tracfone with Verizon service. When phone was purchased it had Android 6, did update to Android 7 in May. On 6/9/2017 Samsung did a system update for Android 7. That's when this issue started. Now any sms text message is sent, it displays the working circle next to text. The message is sent almost immediately but the working circle contiues for about a minute or two and then displays failed to send, with options to resend, edit or cancel. Very frustrating to continue to receive failed to send messages. I changed sim card to try a Tmobile and messages would send normally using GSM network. There seems to be a software issue with these phones using Verizon service. Sent my phone to Samsung for factory service. They changed some internal components and sent phone back. There repairs did not correct the problem. Still continue to receive failed to send error messages.
I'm having the exact same problem. Verizon branded s7 edge through straight talk. Every text sends but says it fails. I've done every reset it wipe I could but to no avail. I was hoping it would be fixed with the June security update but I was wrong
RE texting issue over WiFi: I have a Galaxy S7 Edge on T-Mobile. I found while on a plane, you of course must first have access to free or paid Wi-Fi. You then must do 2 things. 1) Turn on WiFi calling, and 2) turn on Wi-Fi preferred. Note that Cellular preferred does not work, and must be a glitch. Your phone will remind you to change this setting back to Cellular preferred once you get back to a mobile network when on the ground.
In order to send a text message... Type the text message and send it. Then hold your finger on the text you just sent until a bubble pops up. Click the "send as text message". You may have to do this a few times with each number until the phone recognizes it and it works automatically.
I also having exactly the same problem. I'm using an unlocked Galaxy S7 Edge on Tracfone with Verizon service. Ever since the Nougat update, I keep getting the same failed to send message when sending SMS messages even though the message goes through to the recipient. Everything worked fine with Marshmallow. I tried every suggestion including doing a factory reset on the phone, but still have the same problem.
Same problem as the person above me. I like Android, but they sometimes have software bugs that I feel are inexcusable, such as this. I just came back, getting an S7 after 3+ years on an iPhone, and none of their updates screwed up the most basic of the phones functions. Absolute B.S.! This needs to be fixed NOW!
I had the same problem...my daughter told me how to fix it. Type the text message and send it. Then hold your finger on the text you are trying to send until a bubble pops up. Click the "send as text message". You may have to do this a few times with each number until the phone recognizes it and it works automatically.