Use sed to insert three lines of text after the line that matches a certain pattern

I have a set of files with file extension ovpn and wish to insert into each of them the following three lines:

The above are to be placed after this line:

The desired output should be:

My attempt is:

Code:

sed -i -e '/auth SHA512/a\' \
    -e '\n\nscript-security 2\nup /etc/openvpn/update-resolve-conf\ndown /etc/openvpn/update-resolv-conf\n' \
    *.ovpn

However the above commands add two blank lines after "auth SHA512" and a blank line after "down /etc/openvpn/update-resolv-conf".

Can someone show me how to not add blank lines after "auth SHA512" and a blank line after "down /etc/openvpn/update-resolv-conf"?