Alright. I’m not seeing a similar question, even. It seems that my copy of LO is broken. I can insert a table of contents and I can set my chapters to Heading 1, but my chapters still never show in my table of contents. What am I doing wrong?
Version: 7.2.3.2 / LibreOffice Community
Build ID: 20(Build:2)
CPU threads: 8; OS: Linux 5.13; UI render: default; VCL: gtk3
Locale: en-US (en_US.UTF-8); UI: en-US
Ubuntu package version: 1:7.2.3-0ubuntu0.21.10.1
Calc: threaded
Have you right-clicked on TOC and selected Update Index?
Yes, I have. And it still defies my request to make a toc. 
If you click Help > Restart in safe mode > Continue in safe mode does it work then?
First steps has a number of checks you can make as well as links to some useful info on user profile: First steps to take before submitting a bug - The Document Foundation Wiki
Still no dice, even after safe mode. 
How about with a new document? Keep the default styles and just add some random text. Make some headings using the Headings 1,2, &3 styles. Add a TOC and see if it works. If it does it is probably an issue with your document, if it doesn’t then it is probably an issue with your installation of LO
I had this issue yesterday. The TOC was protected so I couldn’t delete it and remake it so I put the cursor at the upper left next to the title “Table of Contents” and proceeded as if to make a new TOC by doing Insert/Table of Contents and Index/Table of Contents and it just made a new one and overwrote the old one. It doesn’t update as you’re going along making new headings as I thought it might, but this got a new one on there for me.
Best,
Gordon
@AZGordon: TOC never update continuously as your text is modified. You must either right-click in it and Update Index or globally Tools>Update All.
So if you expected your TOC to automatically “follow” your text, this isn’t done and manual update is what is in the present specification.
Outstanding! That’s much easier than what I did, remake the whole TOC.
Urgh. I wrote my book, I made all of the chapters Heading 1 and then I tried to update the ToC and nothing. I feel like something horribly obvious is missing for me. I shouldn’t have to remake the ToC and I shouldn’t have to fiddle this much. I’m very confused.
@wolverine79936: attach a 1- or 2-page sample for analysis (“lorem ipsum” text if ti contains personal or confidential data).