The Kerensky Offensive was supposed to prove that the Russian Provisional Government was in control and that Russia could still field an effective army. Instead, it demonstrated that neither of these were true.
The Kerensky Offensive provoked discontent among soldiers in Petrograd which triggered a Bolshevik uprising against the Provisional Government. The uprising was put down and evidence was made public that the Bolsheviks were being supported and funded by Germany.
With the Bolsheviks relentlessly criticizing the Russian government, the question of war aims came to the fore. When the liberals in the government couldn't give a straight answer, a cabinet shuffle followed, giving socialists more power than before.