Connection errors may happen for many different reasons. Please note that they are not considered bugs, hence please don't send connection error reports. Answering reports of connection errors is very time consuming.
Connection errors may happen
- if the app syncs during a call or if it's interrupted by a call. Many (or most?) devices have no data connectivity during a voice call.
- if you're using power saving technologies or apps that disable data connections after some time (or when the device is in standby). It may take a few seconds for a data connection to recover after it has been re-enabled. If Android triggers a sync during that period you may get connection errors too (even though the data network icon is shown).
- in areas of bad network coverage
- in wifi networks with too many clients or high package loss
- in public wifi networks with an additional authentification when the connection is not yet established
- in large buildings without repeater
- in elevators
- if you're using a dynamic DNS service (like DynDNS). If your IP changed, but the updated address didn't make its way to your device yet or your device still uses the cached address the app will try to connect to the old address and fail (probably with a connection error).
- if your server is not accessible for whatever reason
So please, either disable connection error reports completely or at least don't send reports. This feature is a service for users who want to debug sync issues with their servers.