There are not many factors that could cause RMS connection to go down and not all of them are coming from device itself.
I would first suggest try using auto-reboot functionality on loss of mobile data connection, as this is the most common reason with RMS connection goes down too.
But if it's specifically RMS that goes down and not mobile data connection - please try resetting your router to default factory settings and unregister/register it to RMS platform again.
In overall, RMS connectivity option for auto-reboot is still a great suggestion and I will give it to RnD.
Thank you for you feedback!