I have multiple Elastic Beanstalk apps in two aws accounts. In one of them for all 3 elastic beanstalk apps, Monitoring tab is empty for some reason. In other is displaying metrics as earlier. I do not recall any significant change that could be a reason for this or find any setting that does this. Below is a screenshot of Monitoring tab.
Any pointers, indicators to get it resolve would be highly appreciated. Thanks!
Suggest you check your IAM Service-Linked Roles for Elastic Beanstalk:
There is a specific Service-Linked role for monitoring, and also a procedure for updating an out-of-date default service role. It's possible that the role you are using could lack some of the required permissions.
The general guidance from AWS on that is essentially to create a new EB environment or add the missing permissions to the role by appending policies to that role:
If the default service role lacks the required permissions, you can update it by creating a new environment in the Elastic Beanstalk environment management console. Alternatively, you can manually add the managed policies to the default service role.