Online shopping doesn't work

I have been trying to log into the website to manage my account (see paid amounts, plan next payments and also make a yearly budget for the products I wish to buy) but the website always has "We are experiencing technical errors" when I try to login.

This is not a deal breaker to me because I have convenient access to the shops, but it's annoying that I cannot use this online service. The only time it worked properly was the time I signed up to link my card number to my account.