Tried to copy ssl cert to webmin

I was doing as I usually do… I requested a certificate via Let’s Encrypt, and then I clicked the “Copy to Webmin” button, but something appeared to happen, like packet loss… now webmin does not start up.

service webmin restart

Stopping Webmin server in /usr/libexec/webmin
Starting Webmin server in /usr/libexec/webmin
Failed to open SSL key /etc/webmin/domain.tld.key at /usr/libexec/webmin/miniserv.pl line 4403.

I have verified the key file exists, but I still receive this error.