APIC-EM API concurrent sessions

Was wondering if there is an upper limit on the number of authorization tokens (tickets), that a single user can create. Similarily, is there a limitation of only a single call to certain API resource at a time .Trying to manage PnP device configs using parallel API requests for each of the devices and start getting "Not authorized" errors (HTTP error code 401) while doing requests in parallel. If fallbacking to calling API for each host in a serialized sequence - all the auth issues disappear.

 Dealing with around 30 nodes at the moment,Started  hitting auth erros roughly at a number of 5. In a long term, there may be up to 200 sessions if no workaround is applied (Thinking of either introducing some batching to serialize the requests or just add code to retry the request upon such failure). 

 Most API are async to stop these types of issues. What is the API that you are calling that fails..

 Is it the /file API to upload configuration files.. If so, those are synchronous, and will have a limit.  You will need to batch them.