Blizzard Customer Service of Europe has recently tweeted out they are currently investigating disconnections for Overwatch.
Please head for the official European Technical Support Forum where you will be able to discuss and find details about these issues. As always please avoid Competitive Play, any disconnections will still result in penalties and cannot be reversed. Click here for details about this policy.
EU Blizzard Customer Support is asking for help to trace down the network problem. Head for this thread for details: