In SharePoint 2013 on-Premise I was getting the error
The sandboxed code execution request was refused because the Sandboxed Code Host Service was too busy to handle the request
while uploading and activating the sandboxed solution which contains list definition feature and Feature Receiver in solution galleries under web designer galleries.
But If I remove the Feature receiver and upload & activate the wsp in solution galleries it works fine.
I have tried the following possibilities but no luck:
Changing the registry key from 23c00 to 23e00
Add host entry 127.0.0.1 crl.microsoft.com
Can anyone please suggest the steps to fix the issue