Tab3 plays wifif games but wont login to g play???

[AC Question]

Hi its not the first time ive had problems with this device. The device will play wifi games but wont log into google play for purchases or game progress. It wont log into youtube either. it wont sync to any email. i get connnection error messages when i try. yet in wifi it says stong connection. the strange thing it. this is on my daughters email. I check the passwords too but it does the same on another device. could anyone help me trouble shoot this and find a solution please?