Tried all Solutions but still get the .err

Good afternon Ladies and Gents

 I have a customer that has three seperate SEPM servers on three different networks. 2 out of the three get the .err extension whenever they perform a manual update using the downloaded .jdb file . I have directed them to try all solutions I could find from cleaning corrupt defs , re downloading the file, changeing to keeping 1 definition and  uninstalling Liveupdate and reinstalling it and it still gives the .err extension. Anyone have any other ideas?