This is occurring for one of 2 reasons (all fixed in A3Sync):

1. You don't have all the addons checked in under Addon Groups in the Addons tab. To fix this easily, uncheck the entire Clear Backblast group and recheck it.
2. Assuming the above has been done, your load order may out of sync for your mods. To fix this go to the Addon Priorities pane in the Addon Options tab. Click the red X on the right side to reset addon priorities.

I'm getting kicked off the server for:

This can either be a game or a mod related issue. Please take notes of what exactly if kicked you for.

• Make sure both ACRE and Arma (or Arma 3 Sync) are set to run as admin. The biggest sign that one or the other isn't being run as admin is if people can hear you talking over radio but they're unable to hear you talking locally.
• Try restarting the ACRE plugin. In teamspeak, go to Tools → Options (Alt+P) → Addons and click Reload All at the bottom of the window.
• Try restarting ArmA and teamspeak.

This is sometimes dependent on how your Teamspeak or Windows sound options are set up.

For Teamspeak, check the playback options in Teamspeak and make sure it's set to stereo and 3d positions for clients.

For Windows, make sure your device is set to stereo audio. This can be changed by clicking the Configure button on the device in the Windows playback devices menu.