Problem Capacitor 560 uf 6.3 v

Hello

we use many RouterBoard MikroTik RB411 for comunicaion wireless.

after about 4 month we have a problem with this RouterBoard and it was Blink LED on
RB411 and turn off turn on,

we found solution for fix this problem: xchange “capacitor 560 uf 6.3v Su’scon”

But we want to know :

1- why happen this problem?
2- there is other Sulotion?
3- we use many RB411 and RB433 which not problem yet, what we do to prevent this problem for this RB and new install RB

Thanks