Couldn't Update-Installation Problem message

[technutcounselor]

I keep getting this message when trying to install the system update OPM1.180104.141. Can anyone help me? I've restarted the phone, did a factory data reset and I can't figure out how to fix this.

 

[technutcounselor]

Sideloaded it. Never did that before coming from Apple. I liked it.