No chest after I got an S[Client]

Hello Please help me out i was playing league of legends Ranked i own the champion i played with which i play with Annie i included the match history but i am not sure how you can make sure it's an S but i checked and was so happy when i saw you earned S on Annie i went outside but it didn't give me a chest i have remaining chest to get 2 more and Availiable the other 2 i got them when i was playing with a friend and he got S it worked when my friend gets s but not with me but this wasn't the first time it happened it once happened to me while i was playing Yasuo but i thought it will only happen once not again and anyways all the time i open the game or do anything it say unexpected error happen i don't know why . thanks for listening through and plz fix this because i deserve 2 more chests but unluckily i cant get them . i promise this is no lie and please help me out.