Our services were down for 2 weeks due to issues with ISP.
Out Internet Service Provider was bought by the biggest Serbian ISP, MTS. Our contract with them expired after that and MTS decided to not let us continue with the same contract, due to price hike.
It tooks some time for them to install a new router and for us to figure out they didn’t give us a static IP address as we requested. It also took us some time to realize that the ports couldn’t be forwarded anymore on a dynamic IP adress, as they claim, even though our friends say they still can. Port forwarding on dynamic IP might just be disabled on new routers they install.
Either way, we managed to solve all of that stuff yesterday when they gave as a new static IP address. Now all services are online, but you might get your emails in spam, since we are waiting for them set up a reverse DNS to our domain.