This error could be caused by required additional software packages which are missing or not installable. Furthermore there could be a conflict between software packages which are not allowed to be installed at the same time.
The following packages have unmet dependencies:
flashplugin-ins
situation:
libssl-dev : Depends: libssl1.1 (= 1.1.1b-1ubuntu2) but 1.1.1b-1ubuntu2.1 is to be installed
E: Unable to correct problems, you have held broken packages