Network Access to and from China Mainland

Hello, I have a customer based in Europe which have a subsidiary in China (Mainland) and also do a lot of businesses with China (Mainland). Lately the customer have a lot of issues with accessing websites which are hosted outside China from the subsidiary in China and sees also a lot of delivery problems with emails send to China. The SMTP-Gateway is located in Germany and in the logs we can see timeouts during the connection to the STMP servers in China (Mainland). I suspect that the Chinese Firewall has changed it's behaviour. Have anyone else currently similar issues with communication to and from China? Thanks, Patrick