Hello Koders 
,
I am writing this post to help those who have or may get this issue.
Issue:
Suddenly the .aab building fails at a specific % of process. (Note - If your app was getting built recently and suddenly it dosen’t. Your app may also have some actual error that you could find in the Logs.)
Causes:
- If you have just changed or overwritten your app signing key than you may face this issue.
- It can also happen without any issue because sometimes server may be heavily loaded by built requests.
Solution:
There is no need to worry as this is just a temporary bug, Just keep on trying after several times and your built would be completed.
Hope you have found your solution…