Thank you for your query.
As far as I understood you meant SSL/TLS certificates by saying protection certificates.
1) Could you please elaborate a little bit how did you test that the transmitting interval can't be longer than 15s? As in general you can select transmitting period freely by navigating to Services -> Data To Server -> Data Senders advanced settings. Try setting the period to more than 15s.
2) What firmware version are you currently using? We have recently had a new firmware release, I would strongly recommend upgrading(if you haven't done that yet) and test when ever the same issue reoccurs.
If, after taking earlier mentioned steps, the issue reoccurs. Please, could you navigate to System -> Administration -> Troubleshoot and download the Troubleshoot file. Forward it to me via Private Message.