They say so.
"White House admits Trump’s Ukraine phone call record was moved to secret server"
Reasoning? September 27th article;
"White House officials say that the call was classified, meaning there was nothing wrong in moving it to that server"
https://www.independent.co.uk/news/world/americas/us-politics/trump-ukraine-call-white-house-secret-server-impeachment-a9123536.html
However, the Memorandum was declassified 3 days earlier on the 24th.
So, why is the actual recording still unavailable? "All material" was requested by the Democrats.
https://intelligence.house.gov/uploadedfiles/2019-09-24.eec_engel_schiff_to_cipollone-wh_re_potus_ukraine.pdf
