URL Related Problem

Hello,

CRM has the option of attaching document along with URL.
We are trying to use URL option but in some cases user does not reach to specified location.

Upon study we have found, user has used Symbols (i.e ★、→(double byte digits)), which has caused this kind of problem.

I would like to ask if there is (are) any another condition(s), in which specified URL can not be accessed.

Thanks in Advance,
Yuj