The error message states that the memory limit is set at 128MiB.
Which is strange, as that's a decent memory limit. An add-on is trying to store a ridiculous amount of storage using the DataRegistry, and PHP is running out of allowed memory to store it before sticking it in the database.
@ayushtyagi28 you could try increasing the memory limit (if you're on a dedicated/VPS server) to 256M. If you're on shared hosting, you'd have to ask your host kindly.