I can reproduce your issue.
it has the same cause as this other bug:
https://github.com/spesmilo/electrum/issues/2097the bug was fixed earlier this morning.
you will have to wait for the next release (planned for today or tomorrow), and then restore again from seed.
Hello, ThomasV. After upgraded to 2.7.15, I still can't send any bitcoin because of "incorrect password" issue. And I can't even use private key to import my address in blockchain too, it says my private key is mismatch with the address. In short, I can't use any of my bitcoin in Electrum now... Please help!!! The bug is not fixed yet.