how to solve?
version 2.0.15
That would be a permission issue. If I remember right, there are 2 permissions for accessing PMs, one for reading and another for sending.
ok man where?
In the permissions section.......
to some users of the same group it signals "1 pm" but when they click on it it does not show any pm
that's a completely different issue
how to fix?
clear the cache
not work
Not something 2.0 usually does a lot. Perhaps your host is running some cache that is doing stoopid things? Perhaps their browser has something cached strangely? Perhaps your forum has the numbers wrong? We can only guess with the info you gave.