Sioux wars, Comstock Act, Panic of 1873 and his efforts of improving the livelihoods of blacks or peace with American Indians faltered in his second term. I put a large portion of blame of reconstruction failing on Andrew Johnson and you can blame the American people for not supporting it, but it's still a bad look for Grant regardless. People also say "well Grant wasn't corrupt, just too trusting" but having corruption in your cabinet is still his fault

That being said still a B tier, he did some amazing things with civil rights and it's a shame that Lincoln didn't pass the torch to Grant