unable to install

[SajeshKumar]

Connecting to github.com (140.82.112.4:443)
wget: server returned error: HTTP/1.1 404 Not Found
tar: invalid magic
tar: short read
ERROR: Service 'openvpn' failed to build: The command '/bin/sh -c apk add --update bash openvpn easy-rsa iptables && ln -s /usr/share/easy-rsa/easyrsa /usr/local/bin && wget https://github.com/pashcovich/openvpn-user/releases/download/v1.0.4/openvpn-user-linux-${TARGETARCH}.tar.gz -O - | tar xz -C /usr/local/bin && rm -rf /tmp/* /var/tmp/* /var/cache/apk/* /var/cache/distfiles/*' returned a non-zero code: 1

[SajeshKumar]

full log

Building openvpn
Step 1/6 : FROM alpine:3.16
---> 187eae39ad94
Step 2/6 : ARG TARGETARCH
---> Running in 0e6e95bb771f
Removing intermediate container 0e6e95bb771f
---> db79a1c8010d
Step 3/6 : RUN apk add --update bash openvpn easy-rsa iptables && ln -s /usr/share/easy-rsa/easyrsa /usr/local/bin && wget https://github.com/pashcovich/openvpn-user/releases/download/v1.0.4/openvpn-user-linux-${TARGETARCH}.tar.gz -O - | tar xz -C /usr/local/bin && rm -rf /tmp/* /var/tmp/* /var/cache/apk/* /var/cache/distfiles/*
---> Running in 367306a8af32
fetch https://dl-cdn.alpinelinux.org/alpine/v3.16/main/x86_64/APKINDEX.tar.gz
fetch https://dl-cdn.alpinelinux.org/alpine/v3.16/community/x86_64/APKINDEX.tar.gz
(1/17) Installing ncurses-terminfo-base (6.3_p20220521-r1)
(2/17) Installing ncurses-libs (6.3_p20220521-r1)
(3/17) Installing readline (8.1.2-r0)
(4/17) Installing bash (5.1.16-r2)
Executing bash-5.1.16-r2.post-install
(5/17) Installing openssl (1.1.1v-r0)
(6/17) Installing easy-rsa (3.0.8-r0)
(7/17) Installing libmnl (1.0.5-r0)
(8/17) Installing libnftnl (1.2.3-r0)
(9/17) Installing iptables (1.8.8-r1)
(10/17) Installing libcap (2.64-r1)
(11/17) Installing libbz2 (1.0.8-r1)
(12/17) Installing fts (1.2.7-r1)
(13/17) Installing xz-libs (5.2.5-r1)
(14/17) Installing libelf (0.186-r0)
(15/17) Installing iproute2-minimal (5.17.0-r0)
(16/17) Installing lzo (2.10-r3)
(17/17) Installing openvpn (2.5.6-r1)
Executing openvpn-2.5.6-r1.pre-install
Executing busybox-1.35.0-r17.trigger
OK: 14 MiB in 31 packages
Connecting to github.com (140.82.112.4:443)
wget: server returned error: HTTP/1.1 404 Not Found
tar: invalid magic
tar: short read
ERROR: Service 'openvpn' failed to build: The command '/bin/sh -c apk add --update bash openvpn easy-rsa iptables && ln -s /usr/share/easy-rsa/easyrsa /usr/local/bin && wget https://github.com/pashcovich/openvpn-user/releases/download/v1.0.4/openvpn-user-linux-${TARGETARCH}.tar.gz -O - | tar xz -C /usr/local/bin && rm -rf /tmp/* /var/tmp/* /var/cache/apk/* /var/cache/distfiles/*' returned a non-zero code: 1

[sprait]

TARGETARCH variable is not defined in your case.
It looks like you use old version Docker packages, try to update them