Having issues reinstalling El Capitan xo

What was your version of macOS prior to wiping everything. You can't reinstall OS X El Capitan if you had macOS Catalina installed. You can try wiping the SSD/HDD to have a GPT partition map if it doesn't already and then you should format Macintosh HD to be HFS (macOS Extended). Then you should boot into macOS Recovery and reinstall macOS. Make sure you are connected to the internet. If that doesn't work, then try installing the original version of macOS that came with your computer then upgrade to El Capitan. Check out this link: https://support.apple.com/guide/mac-help/reinstall-macos-mchlp1599/mac.