The reason why your device is invalid is that your device version and app version don't match. Different Memobird versions using different apps, for instance, Memobird G1 has to be used with its Chinese app version, it won't work if you use it with the North American app version.
So, to solve your issue, we need to find the right app for your device. To do that, first, we need to find out what Memobird device version you have. If you're not sure what's Memobird version you have, please check this article
IF YOU HAVE MEMOBIRD G2 NORTH AMERICAN VERSION
You need to use the North American app called "Memobird-was Mymemobird" that is available worldwide, except in China.
To download the North American app version, please scan the QR code below.
Or download it here.
IF YOU HAVE MEMOBIRD G1, MEMOBIRD G2 CHINESE VERSION, OR MEMOBIRD G3(GT1)
You need to use the Chinese app called "咕咕机" that is available in China only.
Please be aware that Memobird G1, Memobird G2 Chinese Ver., and Memobird G3(GT1) along with its Chinese app are managed by a China-based company called Intretech, Inc. (not us).
Therefore, if you have any issue with your Memobird G1, G2 Chinese Ver., or Memobird G3(GT1), please contact their support below for help. Because it's out of our capacity to help you.
MEMOBIRD CHINA SUPPORT
Memobird China Email Support: firstname.lastname@example.org
After that, try to bind/add your Memobird again.