certificate error for repos.php.earth

[vtotare]

Hi Team,
I am using below approach on Alpine linux to build my PHP container.

Approach:
apk add --no-cache wget ca-certificates
&& wget -O /etc/apk/keys/phpearth.rsa.pub https://repos.php.earth/alpine/phpearth.rsa.pub
&& echo "https://repos.php.earth/alpine/v3.8" >> /etc/apk/repositories

However, I started receiving below error since yesterday while building docker container. Can you please help me on this and what is this issue. I am not getting this error while accessing site in browser.

Error:
#9 4.239 fetch https://repos.php.earth/alpine/v3.8/x86_64/APKINDEX.tar.gz
#9 4.530 139816800693196:error:14007086:SSL routines:CONNECT_CR_CERT:certificate verify failed:ssl_clnt.c:1132:
#9 4.533 ERROR: https://repos.php.earth/alpine/v3.8: Permission denied
#9 4.533 WARNING: Ignoring https://repos.php.earth/alpine/v3.8: No such file or directory

[Maikuolan]

Cross-referencing due to related: phpearth/alpine#32
Cross-referencing due to related: phpearth/PHP.earth#37