Using Writer (LibreOffice 24.8.3.2) on a Mac Mini (M4) running Sequoia 15.1.1.
I can manually insert a Page Break using Insert:More Breaks:Manual Break, but cannot insert it from the menu or using Commane-Enter.
On the Insert Menu, Page Break is grayed out.
This is occurring on new documents and older ones.
Tried saving as .odt and .docx
Tried pasting as unformatted text
Tried versions 7.6.7.2 and 24.2.4.2. They behave the same way
Could you be more specific on your procedure? There are contexts inside which it is forbidden ot insert page breaks: footer, header, footnote, endnote, endnotes pages.
Cmd+Enter is the shortcut for “ordinary” page breaks. Insert>More Breaks>Manual Break is for “special” breaks when you want to change page style or to restart page number.
In case this could be related to some formatting, could you attach a sample file where this happens?
Thanks for the quick response.
I was having the issue across several documents, old and newly-created. Now it appears to be working as it should. The only thing I’ve done is to close and restart the program
As far as I can tell I’m in the body of the documents in question.
I’ve attached a sample file.
It was created from an empty document where I used Paste Special to insert the text as Rich Text.
The page break was inserted using the More Breaks menu choice.
clicking anywhere in the document the Insert Page Break menu choice appears grayed out.
I hate when problems solve themselves. 
Dave
Page Break sample.odt (19.3 KB)
No problem with your sample. As you say, difficult to diagnose when things settle by themselves.
Just a side note: your whole sample is direct formatted (everything is done manually). This is equivalent to use a mechanical typewriter. Note that Default Paragraph Style has a special role in Writer: all its settings are forwarded to all other styles (which are free to override some of these). It is a handy way to define your preferred typographical attributes shared all over the document (headings, narrative, notes, captions, …). Consequently, it should not be used for real text because you’ll be tempted to customise it and you’ll be surprised by the side effects.