The system is hosted on an architecture that uses forests and tree of domains.
The implemented code accesses the AD of context in which it is running.
In this case, the AD responsible for the context of the application was not updated. The users who have problems were not with the e-mail address filled this AD.
And when it consulted the main AD, with some tool for this, the information was there correctly, which caused confusion.
After some investigations was detected confusion.
That's it. Problem solved!
Thanks for the cooperation!