Yes, I had this problem for the last 3 months I was playing. Did it on my old PC, did it on my new PC, talked to my ISP and everything looked normal to them. Talked to SIMU and they said it was my IP.
I have had zero problems with anything else, just Gemstone.
It's ok though, SIMU will never see my money again. As far as I'm concerned it's operated by thieves now anyhow.