Strange...I have the same error, but Pixel tells me that they've never seen this error before, and tell me that it's my ageing iPad at fault. I have done everything they've suggested, be it uninstalling/reinstalling the game, rebooting my iPad, making sure I have the latest version of the game, the latest iOS...
I always have a strong WiFi signal, my kids are watching Netflix on the same connection, and I never have any issues with my other Internet-dependent games . I've connected via my iPhone's hotspot as well, but it still happens.
I'm getting rather tired of this, and I'd hate to have to delete the game, because I enjoy it so much.
Don't know what else I can do... ;-(