Sorry to bother again, but now I run into a different problem with this. I set `gnutls-algorithm-priority' to "NORMAL:-VERS-TLS1.3" as suggested in that bugreport. This does work fine locally. However, when I use the same code on Travis CI for automated testing, I get the following error: gnutls.c: [1] (Emacs) connecting to host: stable.melpa.org gnutls.c: [1] (Emacs) allocating credentials gnutls.c: [2] (Emacs) allocating x509 credentials gnutls.c: [2] (Emacs) using default verification flags gnutls.c: [1] (Emacs) setting the trustfile: /etc/ssl/certs/ca-certificates.crt gnutls.c: [1] (Emacs) gnutls callbacks gnutls.c: [1] (Emacs) gnutls_init gnutls.c: [1] (Emacs) got non-default priority string: NORMAL:-VERS-TLS1.3 gnutls.c: [1] (Emacs) setting the priority string gnutls.c: [2] ASSERT: gnutls_priority.c:832 gnutls.el: (err=[-50] The request is invalid.) boot: (:priority NORMAL:-VERS-TLS1.3 :hostname stable.melpa.org :loglevel 2 :min-prime-bits 256 :trustfiles (/etc/ssl/certs/ca-certificates.crt) :crlfiles nil :keylist nil :verify-flags nil :verify-error nil :callbacks nil) Package refresh done Debugger entered--Lisp error: (gnutls-error #> -50) signal(gnutls-error (#> -50)) Travis CI (Ubuntu distribution Trusty) has an ancient GnuTLS version 2.12.6. As far as I understand, it doesn't know about TLS1.3 and therefore the attempt to disable it fails. Is there a way to use "NORMAL:-VERS-TLS1.3" in "do not fail" mode? Maybe I could somehow query if the library knows about 1.3 first? Paul On Sat, 25 Jan 2020 at 16:33, Noam Postavsky wrote: > On Sat, 25 Jan 2020 at 09:55, Paul Pogonyshev > wrote: > > > > (file-error "https://elpa.gnu.org/packages/archive-contents" "Bad > Request") > > > > for me. Also fails if I replace "https" with "http" in the command, > > though with a different error. > > The https failure is Bug#36749, though I'm surprised to hear that it > fails with plain http as well. > > > * The command with different Emacs version: 24.5, 26.3 and 28.0.50 > > (trunk). > > Is your 24.5 Emacs linked against an older version of libgnutls? > Otherwise I would expect it to have the same problem. >