Hi Vishu Sidana, the problem is that you are allow up to 10000 trades, so upgrade your plan.
or try to run 5 backestets at each one change :
self.SetStartDate(2014, 5, 15)
self.SetEndDate(2014, 12, 1)
self.SetStartDate(2014,12, 1)
self.SetEndDate(2015, 11, 1)
self.SetStartDate(2015,11, 1)
self.SetEndDate(2016, 11, 1)
self.SetStartDate(2016,11, 1)
self.SetEndDate(2017, 11, 1)
self.SetStartDate(2017,11, 1)
self.SetEndDate(2018, 11, 1)
if the exception is throw again "You have exceeded maximum number of orders (10000), for unlimited orders upgrade your account.", just reduce the period between backtest. at last you average the stats of all your backtests.
by the way. what Jared said, you are rebalacing to frecuently, and for that so many orders.easily reach 10000 limit
here an article
https://www.schroders.com/es/es/inversores-profesionales/vision-de-mercado/revision-mensual-de-mercados/why-churn-is-not-necessarily-burn/