Dublicate meetings Samsung Galaxy s2

Hi. One user have problems with samsung galaxy s2 in company. Calendar always dublicate meeting in calendar. I checked sync with another galaxy s2 and the problems is still appear. I checked sync the user with iphone and in iphone all works good. All another users works good with galaxy s2. I enabled OWA logs. I tried to search how to read the logs, but i didn't find something helpful 

Need some help to resolve

Thanks

Michael