This article provides a solution for when you are unable to save an entity in the Adobe Commerce backend. For example, when you cannot edit and save a specific
This issue can affect all Adobe Commerce versions which have Max Session Size configured. This was added starting from Magento Open Source 2.3.7-p1 and Adobe commerce (all deployment methods) 2.4.3.
When you try to reconfigure your store the page reloads and your changes are not saved. A message can be seen in
[2021-11-27 00:30:52] report.WARNING: Session size of 418056 exceeded allowed session max size of 256000.  
Steps to reproduce:
An example of store configuration not being saved:
The rule is set to inactive.
This issue is related to new functionality introduced recently that has impacted the Max Session Size. See Session management in our developer documentation.
Increase the “Max Session Size” value in (Stores > Configuration > Advanced > System > Security > Max Session Size).