What does this mean? "This document cannot be packaged due to missing plug-ins. Please install or activate these plug-ins: AdMan_Plugin.InDesignPlugin"?
I have searched the Adobe site and the forum and can find no reference to an AdMan plug-in.
I really need to package my file.
InDesign CC 2021 16.1
iMac 5K 27-9nch 2019
3.7 GHz-6-Core 9ntel i5
32 GB Ram
It is certainly a third-party plugin. Export your InDesign file to idml and open the idml file, then save this file, it should be OK after.
Try exporting your file as IDML and then opening from that file. This process will often strip out links to missing plugsins, so that you will be able to package your file successfully.
Based on a quick search, I found reference to AdMan as a Plugin for exporting to Wordpress. Does this sound familiar to you? Or is this a file that has come from someone else? In any case, this particular PlugIn was discontinued in 2018, so there's no new (or old) version for you in case it was something you had used, so if you have a lot of old files, this will come up again!
Regardless, if the Export to .IDML approach doesn't work for you, someone has created a plugin in which can strip the missing plugin hooks. I have no experience with it so can't vouch for its efficacy, but you can take a look here for info: