Thats odd, your friends list may be full try deleting some of your older friends and see if it works try that OR you may just have a glitch reset and download
Your food or item list could be full . The limit is 32 items or foods in each food storage or item storage. Use an item or throw away an item if it is your items which are full. Still not working? Eat up one of your foods and then try it again. It should work .
Omygosh, YOU DONTHAVE TO DELETE YOUR FRIENDS!!!!!!!!!!! Its because you have more then 15 meals or snacks in your inventory. Give one to your tamagotchi and them try to connect again. That happened to me. Hope this helps!!!!!!!