We have several Workflows (2013) starting when an item is created. One of these Workflows does a HTTP call to create a subsite via rest api. Many times this Workflow will take up to a day (!) to complete. One of the actions after the HTTP call is to update a field with the newly created Subsite URL. First we were thinking the API call itself was the culprit as I put an action to log something to the History right after the HTTP call and it does not log until hours afterwards. Now today I discovered that the Subsite is actually created but still the log to History is not happening and the Workflow is stuck until hours after starting it.
There are no errors in the log.
Also, there were days when the Workflow finishes in a few minutes.
Any advise on how to find out what is going on and why the Workflow takes so long most times?