We have moved your thread over to the SimCity > Miscellaneous Issues forum.
We have an article available here for some of the basic steps you can try: http://help.ea.com/en/article/how-to-troubleshoot-crashing-and-freezing-issues/
Among the advanced steps, #3 specifically is related to networking, which would fit your observation.
Let us know how you get on afterwards.
Cheers,
Nils