Mods were used prior to play sp-tarkov but after not being able to login, I reinstalled and registered again. I was met with the same problem and couldn't log back into the launcher. I have repeated this process at least 2-3 times. For example I would put in my username for the launcher and put in my correct password and it would say, "Incorrect username or password," or at least something along those lines. I'm really only allowed to register, hope I don't get logged out, and play until then. It's not a problem with the mods so I really have no idea what it could be.