NO-IP is free if you confirm your host name every 30 days. They send you an email warning that you need to take action. Each time they ask if you want to upgrade to the paid service. I have kept my...

After you reset the router to factory specs. the user id and password are both "admin". Many times it is printed on the bottom or back of the router.

You may need to update the firmware. https://www.tp-link.com/us/faq-781.html

see https://www.manualslib.com/manual/1239913/Tp-Link-M7310.html as it shows EU countries but not US. Not sure why. Also found this on an AT&T which uses the same type of system a T-Moble....

Since your IP changes I see your need to have the router update it especially if you need to connect from outside your network. When I travel, I like to check my cameras. I tried to set NO-IP up on...

please let us know what you find. Does power off/on just the router reestablish the connection? Does power off/on just the PC reestablish the connection?