Pokefarmer's alert means what?

[tktk]

As attachment file indicated:INFO <b><font color="#0094FF">[15:06:57]</font></b> Session expired. Relogging.
The alert message shows "Session expired. Relogging."every 30 minutes in pokefarmer's message box,Why?
Does it mean anything errors?

 

[leon0514]

same problem, i dont have any idea. hoping someone knew it.