iPhone app stopped working

Hello. I just changed my internet/cable provider and the iPhone app (Home+) stopped working. Any ideas? Thank you!

1. Ra2 processor has been disconnected from the network.
2. New modem/router combo has new IP range and Ra2 processor needs a reboot to get new DHCP address.
3. Same as above but Ra2 is static IP on old range and reboot won't fix it- new static IP will need to be set.

The first set of troubleshooting steps that you must do is on the smartphone side. Below are the things that you must do.
Toggle wifi on and off

Simple step are sometimes effective solutions so if you haven’t tried turning wifi on and off, we suggest that you do it at this time. Turning wifi off means the wifi service is disabled as well, which can, in turn eliminate the bug that may have developed for some reason.
Toggle Wi-Fi Assist

Wi-fi Assist is a feature that ensures your phone will not lose internet connection by automatically switching mobile data on if wifi connection becomes poor or out of range. If you enabled Wi-Fi Assist, consider turning it off for a few seconds. Then, simply turn it back on and see if your wifi connection works properly.
To toggle Wi-Fi Assist on and off, official site follow these steps:

1. Open Settings apps.
2. Tap Cellular.
3. Scroll down to the bottom and look for Wi-Fi Assist.
4. Toggle Wi-Fi Assist ON and OFF for a few times.

If you’re lucky, it may help in resolving the problem.
Reset network settings

Fixing any network-related issue should involve this troubleshooting step. Resetting your iPhone’s network settings does the following:

• deletes all wifi networks and their passwords
• resets Wi-Fi Assist feature back to ON
• deletes any VPN information such as server names, VPN type, password, among others stored in the device

To reset your iPhone 7’s network settings, do these steps:

1. Open Settings app.
2. Tap General.
3. Tap Reset.
4. Tap Reset Network Settings.
5. If prompted, enter your passcode.
6. Tap Reset Network Settings.

Do a factory reset

If resetting network settings won’t help, the next logical troubleshooting step is to perform a factory reset. As the name suggests, all software settings will be returned to their defaults. If you haven’t tried doing it before, here’s how:

1. Create a backup of your important files via iTunes or iCloud.
2. Sign out of your iCloud account (if applicable).
3. Go to Settings.
4. Tap General.
5. Tap Reset.
6. Tap Erase All Content and Settings.

Try connecting to a Wi-Fi network in a different location.

If your phone will continue to fail to connect to the internet after doing a factory reset, try to see if your iPhone can work fine with another wifi network. If you’ll encounter the same problem, that’s a confirmation that you have a bad hardware. Contact Apple for more support.
If, on the other hand, the issue disappears when you connect to another wifi network, proceed to router troubleshooting.