I’ll have to admit that finding a complete answer to this question is proving to be quite challenging.

The Simpsons Tapped Out has a limit of 100 friends, and if you reach this limit, you get a message saying that there has been an “unexpected error”. You also get this message if the person who sent you the invite also has 100 friends by the time you accept. The message may also appear when the person you’re trying to invite or add hasn’t downloaded the latest update. And despite improvements made recently by EA, you sometimes get this message when you are trying to add someone who is using an international version of the app that doesn’t “speak to” yours.

Now any of these could be the problem if you’re adding people from the Facebook page or another online source. But what about when you know that the person you are trying to add doesn’t have 100 friends and neither do you?

EA have indicated on their Answers site (at http://answers.ea.com/t5/The-Simpsons-Tapped-Out/bd-p/The-Simpsons-Tapped-Out) that this is an issue they’re aware of. It may be worth contacting a game advisor through https://help.ea.com/contactus .

One suggestion is to try and resend the requests and get your friends to do the same. When you try this, though, it’s important to know that it can take anywhere up to 36 hours for the request to come through – even if your friend is sitting right next to you.

I realize that this isn’t a complete answer, so I’ll keep looking on this and as soon as I find out more, I’ll update this post.