Using an unmaintained browser applet for entering credentials isn't the best idea in my opinion.
It is sad we never saw a full port of a general web browser to the 3DS platform. It would have been a nice addition to the console. Alas, whenever anybody asks for a 3DS browser the know-it-all people show up asking -- in condescending manner -- "Don't you have a smartphone?"
(As if the possibility to use a different, arguably better, device would answer the question for a 3DS browser)
Enough repeating myself. I just had to put it here before anybody comes in with the "Use your phone!" stuff.
The unmaintained browser applet doesn't have either enough resources (RAM) or support for latest web technology. Not being a pleasant experience to use the forum with it is expected.