Having issue with applying CU23 onto Exchange 2013
What is the version of your .Net framework? If you upgrade exchange 2013 to CU23, you should install .Net framework 4.8 then to upgrade to CU23.
Could you download the exchange 2013 cu23 install file in microsoft blog and check if this issue continues?
As Vick Vega has replied above, you could follow the guidance and run install exe again.