iphone 8 plus hot spot keeps disconnecting

Hi everyone I am have a trouble with my iPhone 8 plus, the hot spot keeps disconnecting, so when its connected to iPad will work for about 20 minutes and the disconnects, the same when connected to my laptop it cuts out , I have googled and tried everything but nothing seems to fix the cutting out of the hot spot, if I remove sim card and put it in an old iPhone 6 plus, I dont have the problem the hot spot works fine so there appears to be something wrong with the iPhone 8 Thanks in advance Craig