When you get a connection error, it is most likely one of two things:
1. Your internet is having some issues and you are unable to connect to the game. This can happen when your internet is intermittent or if the network you are using is bogged down by things such as Torrents, streams, or large downloads.
2. There may be some issue with server connections.
-For server related issues check the Official Facebook Page for all the latest game news and server updates for Brave Frontier.
If you are in the middle of a quest and you experience it, the best course of action is to just wait it out. Go to the Brave Frontier Global Facebook page and check for updates.
If there are no server issues, you should move to a spot with a better signal or wifi connection to see if you can continue your mission without wasting your progress from restarting the app or device.
If you are sure that you have a stable connection and found no updates regarding the server, you can always try to do a Basic Troubleshooting first before you sending a report.