error on tlmgr

[semih ozlem]

Hi I am trying to run update of texlive, that has been downloaded from
debian repository.
When I run the update command as below, I get the response below. What
should I do

Thanks in advance for your help.
-----------------------------
user at debian:/media/user/sd/latexfiles_sample$ tlmgr update --all
(running on Debian, switching to user mode!)
query_ctan_mirror: Programs not set up, trying wget
cannot contact mirror.ctan.org, returning a backbone server!

/usr/bin/tlmgr: signature verification error of /tmp/dtiRH6vt47/nBHVmI8h_b
from
http://www.ctan.org/tex-archive/systems/texlive/tlnet/tlpkg/texlive.tlpdb:
cryptographic signature verification of
  /tmp/dtiRH6vt47/F6Qp6G4owt
against

http://www.ctan.org/tex-archive/systems/texlive/tlnet/tlpkg/texlive.tlpdb.sha512.asc
failed. Output was
gpg: Signature made Sun 19 Jul 2020 02:58:16 AM +03
gpg:                using RSA key 4CE1877E19438C70
gpg: Note: trustdb not writable
gpg: BAD signature from "TeX Live Distribution <tex-live at tug.org>"
[ultimate]

Please report to texlive at tug.org
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