The de facto Law Officer for Public Benefit in England and Wales (LawPB) notes that the Attorney General was forced to resign by the Prime Minster on Thursday 13 February 2020. The precise reasons for this, as part of the ministerial reshuffle, were not publicly disclosed.
The LawPB made clear in his Closing Article no. 1 of 31 October 2019 (at pages 6-7) that if he had been in the position of that Law Officer of the Crown he would have resigned on 25 September 2019, i.e. the day following the Supreme Court judgment on the decision to prorogue Parliament for five weeks. The Court found that Her Majesty the Queen had been led into illegality by the advice she received from the Prime Minister on prorogation. See https://www.directionofconflict.org/closing-bulletins
Specifically, LawPB claimed that the Attorney General had not acted in good faith in providing that legal advice because, however sincere his view, he did not treat Her Majesty fairly. Moreover, nothing has yet been done, as far as is known, to prevent a recurrence of such unfairness.