Have you migrated to a microsoft account and got a confirmation e-mail for it? Because for me, my Mojang Account doesn't even seem to work anymore. Anyways, like I said, try downloading the Win7 launcher and log in with your microsoft account. (if you have sucessfully migrated and got a confirmation mail) That worked for me.
You can also check if the migration worked by logging into minecraft.net via your microsoft account and checking your account settings. I saw that my minecraft skin was set up correctly and that my expired realm was listed, so I knew the migration worked, but apparently the launcher didn't.