Problem with encoding while sharing on Facebook

Hello,

I run multiple websites on WordPress and the two most crucial ones have the same problem when sharing their articles on Facebook — the encoding is totally messed up. I am using Czech characters such as ěščřž.

Previously, all worked fine (and on the other websites is still does) but for whatever reason http://euroseptik.cz and http://mmister.com is not displaying correctly on FB.

I tried googling the problem but no solution seems to solve it.

Could somebody please help me? I’d really aprreciate that.