Multiple port installations @ 2.6.3 fetch failures even with manual download

[jarodcg (Jarod Gouldie)]

I'm attempting to run

sudo port install gnuplot

on Catalina v.10.15.7 but it keeps getting hung up on installing AquaTerm, outputting:

--->  Fetching archive for aquaterm
Warning: Your DNS servers incorrectly claim to know the address of nonexistent hosts. This may cause checksum mismatches for some ports. See this page for more information: <https://trac.macports.org/wiki/MisbehavingServers>
--->  Attempting to fetch aquaterm-1.1.1_0.darwin_19.x86_64.tbz2 from https://packages.macports.org/aquaterm
--->  Attempting to fetch aquaterm-1.1.1_0.darwin_19.x86_64.tbz2.rmd160 from https://packages.macports.org/aquaterm
Error: Failed to archivefetch aquaterm: Failed to fetch signature for archive: The requested URL returned error: 504 
Error: See /opt/local/var/macports/logs/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_aqua_aquaterm/aquaterm/main.log for details.
Error: Follow https://guide.macports.org/#project.tickets to report a bug.
Error: Processing of port aquaterm failed

When I change DNS to a public server (tried several, e.g. 1.1.1.1) and cleaned before installing, the first Warning line disappears but otherwise I get the same output. I get a similar issue attempting to install other packages, namely subversion and FFmpeg - returning a 504 error from packages.macports.org. I attempted manual installation of AquaTerm using tar.gz files from mirrors saved in the specified paths as per:

port distfiles aquaterm

and following the directions under the Fetch Failures section of the Problem Hotlist but this had no effect. My Xcode version is 12.0.1, and I have command-line tools installed, version 12.0.0. I've installed other ports with no issue; these are the first installations I've attempting since getting command-line tools, if that's relevant. I've attached the log generated from the attempted gnuplot installation.

[jmroot (Joshua Root)]

#61270