Kakashi did not fail any students after Team 7 in the original and Shippuden series, but he came very close in the Boruto series.
In the Boruto series, Kakashi offers to be the proctor during the graduation exam and the only student to pass is the one who takes the bell from him. Kakashi states this because he does not want an entire generation of students with defiant attitudes to become shinobi during the time of peace.
Iruka suggested that Kakashi not be too hard on the students come the final exams. Kakashi clarifies that even in peaceful times, they can't allow students with contemptuous attitudes to become shinobi, and as such will be as challenging as ever.
With that, Kakashi stated during the exams that only one student will pass - the others will fail.
During the practical test of the exams, the students were left awe-stricken that he was to be their head proctor. It was explained that while Shino Aburame, Anko Mitarashi, and Konohamaru Sarutobi would be evaluating the students' respective performances in a 24 hour field combat, ultimately only one student could pass; that student would be the one who takes the single bell from Kakashi's hip
However, much like the original series, they all learn the true lesson of the exam and Kakashi passes every student
Ultimately, time ran out before anyone could get the bell. Despite Boruto's plan failing, Kakashi passed everyone, noting that they succeeded in the true goal of the test: team-work and loyalty.