I updated all masternodes to 10.15.13
But i have
Inactive (0%) problem in some.
What is the problem?

I had the same thing on a couple of my MN's
i just now tried to start it up on the local wallet as well. will keep you posted on if that works for me.
Yea I have all my MNs as "inactive"
there too. And the balance is slightly off on one of them as well. Sup?
I have one out of 5 that is ok now, but rest is inactive.
Even the start from local wallet didnt change this, however when i do the darkcoind masternode list grep command, they all return : "1"
so don't know if i should trust the server or the MN sites