Hi @sns ,
To narrow down your issue, Could you share with me the specific actions of your workflow like below?
By the way, what “It is not allowed me to do so” means? Could you share a snapshot of the specific error message in SharePoint Designer 2013 and what operation are you executing when you encountered the error message?
As you mentioned that it is an issue after migration, was this Workflow created in your old SharePoint 2010 and whether it worked fine in SharePoint 2010 or it was created after migrating to SharePoint 2016?
Also, please check Workflow History to find whether there are some useful information or errors in it:
Try to republish your Workflow in SharePoint Designer firstly. If the issue still exists, try to recreate a Workflow identical to it may also give a favor to you, test again in your environment.
I hope this information has been useful, please let me know if you still need assistance.
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