Why can't I install packages on an LTS release? [duplicate]

Solution 1:

Those packages are in the repositories, but you're trying to install obsolete versions that have been superseded and removed. That's why you are getting a 404 error.

Work backwards:

• You're getting apt 404 errors because your local database of packages is out of date. You update that database using apt update. For most folks, that's all they need to do.

• But your specific case is wierder: apt update is also giving you 404 errors.

  There are two possible causes:

  1. You are using a bad mirror. (change mirrors)
  2. Your network is blocking access to the mirror.

  Figure out which of those two is the culprit.