“EXCEEDED_MAX_SIZE_REQUEST: Maximum size of request reached. Maximum size of request is 52428800 bytes.” error
During the deployment process, a zip file is sent to Salesforce. If the size of this file exceeds the defined limit you will encounter this issue. However, in some cases, you might encounter this problem even though you deploy a file which isn’t likely to access this limit. For example, a single Apex Class.
Detection of the Root Cause:
The contents of this zip file are created from the promotion branch- so go to the deployment record getting the error and open the promotion branch by clicking the link. If the link doesn’t open, copy the whole link and search for that promotion branch in your git repository.
Review the root folder of the promotion branch for any zip files that shouldn’t be a part of the promotion branch. To see these files, scroll down to the end of the folder.
Important: You should make sure that you are checking the root folder of the promotion branch.
These zip files are not a part of your deployment. Delete these zip files from the main branches - branches related to your environments like development, production, etc.- so they will never be copied to the promotion branches again.