This procedure is only needed if you like to link Azure DevOps to StoriesOnBoard only on story cards level.
Some work items (like issues) in Azure DevOps doesn't have story point or effort field by default. Like that StoriesOnBoard can't sync with those fields, unless we add them manually. Let's see how to do that.
In case you selected the issue for example as "Exporting work item type" and also checked the option "Synchronize estimation changes as Story points or Effort" you will get the following warning message.
To solve this problem, please go to DevOps and open up one of the problematic work item (in our example i'll open up an issue work item), then from the "..." menu on the right side select "Customize".
Click on "New field", select "Use an existing field" and Story Points or Effort from the drop-down, click on "Add field".
Now you can get back to StoriesOnBoard and validate your configuration. After this process, the estimation sync should work between the tools for these work item types.