Clearsigned file isn't valid, got 'NOSPLIT'

[rmutili]

Not possible to install application, error log attached.

Sending build context to Docker daemon 53.25kB
Step 1/9 : FROM ushahidi/php-fpm-nginx:php-7.3
---> b4db8dd1519e
Step 2/9 : WORKDIR /var/www
---> Using cache
---> 1e69d13dfa0d
Step 3/9 : RUN apt-get update && apt-get install -y unzip rsync netcat-openbsd supervisor cron git && apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
---> Running in bb2797495283
Get:1 http://security.debian.org/debian-security buster/updates InRelease [34.8 kB]
Get:3 http://deb.debian.org/debian buster InRelease [122 kB]
Get:4 http://deb.debian.org/debian buster-updates InRelease [56.6 kB]
Get:5 http://security.debian.org/debian-security buster/updates/main amd64 Packages [610 kB]
Get:2 https://packages.sury.org/php buster InRelease
Err:2 https://packages.sury.org/php buster InRelease
Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
Get:6 http://deb.debian.org/debian buster/main amd64 Packages [7909 kB]
Get:7 http://deb.debian.org/debian buster-updates/main amd64 Packages [8788 B]
Reading package lists...
E: Failed to fetch https://packages.sury.org/php/dists/buster/InRelease Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
E: The repository 'https://packages.sury.org/php buster InRelease' is not signed.
The command '/bin/sh -c apt-get update && apt-get install -y unzip rsync netcat-openbsd supervisor cron git && apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*' returned a non-zero code: 100
ERROR: Service 'ushahidi' failed to build : Build failed