Hi, I have problem configuring stock mail app to be used with our company MS Exch. server. Everything goes well at start but after few hours notification pops up "Sign in failed, password has been changed". Password has not been changed and when you press refresh it syncs ok. And again after few hours same error. This is happening for the first time. It perfectly works on LG Nexus 4 with Andr. 4.4.4, Samsung Galaxy S3 and various other versions of Android and different manufacturers. It`s happenig only on Galaxy S5 with latest updates and all. What to do? Tnx in advance.