I created a simple contract that increases 'i' when function called.
And I sent 10000 transactions (called the function 10000 times by loop) through my dapp.
After that, my dapp could not work well.
For example, I sent 500 transactions more, but just 100 transactions were accepted. (even very slowly accepted)
I changed my account to new one, then my dapp worked well.
But when I changed my account to old one again, my dapp doesn't work.
I think that my account has some problem.. like blacklisted.
Does ethereum blacklist malicious account?