Apache OpenOffice Community Forum

I saved a Writer file as a .docx with a password. When I enter the password to open the file, it tells me that "The password is incorrect. The file cannot be opened."
I replicated the issue with a new file, to confirm that I was in fact using the correct password.

Any ideas?

Welcome to the Forums.
A search for your problem brought back this topic, which, in turn, refers to this topic
You can read those topics, but to summarize, the solution appears to be to open your file using LibreOffice.
We do not recommend using the .docx format, and, in fact, OpenOffice doesn't have the ability to save in that format. LibreOffice does.
Your forum signature should be updated, as there is no OpenOffice 6.2.1.2 version (or at least, not yet).

Solved, 15 character password limit.. It cut off the end of my password.

I confirm that LibreOffice cuts off the final "f" from password 0123456789abcdef when saving password encrypted docx. It does not do so when saving the same file in Open Document Format with password encryption.
LibreOffice's save-as dialog offers pgp encryption for xlsx. When you give a try, you get a dialog to select the key and the warning about foreign file format, the file is saved but remains unencrypted. Pgp encryption works fine with Open Document, of course.

LO 6.4 fixed the issue with max 15 char passwords in xlsx
https://wiki.documentfoundation.org/ReleaseNotes/6.4