Pretendo not working, MH4u

[heady stirrup]

Friends and i tested the online connection a few days ago, and it went fine. Now, it's not working at all - and just constantly showing us this error screen. Any tips? Thanks in advance ♡

Update: I've managed to pull an error code, from going into friends list. 001-0103

[stray root]

For 001-0103, open your friend list and erase any friend card(s) whose friend code is made of question marks (????-????-????)