Paragraph justification in Photoshop is not available for the following reasons:
Font issues: Some fonts may not have been designed with the alignment in mind, or the font itself may have some flaws that prevent it from being aligned.
Text box setting issues: Improper size, position, or margins of a text box can affect the alignment of paragraphs. For example, if a text box isn't wide enough to fit the text in a paragraph, the justification might not work.
Software version issues: Different versions of Photoshop will vary in terms of features. Older versions may have issues with text alignment not being available, either because the software developer didn't design it with the feature in mind, or because it couldn't be implemented for other technical reasons.
Please note that these are just some of the reasons that may cause the paragraph justification feature to be unusable, and the specifics may vary depending on factors such as personal actions and Photoshop versions. If you encounter related problems, we recommend that you try to adjust the font, text box settings, or update the software version to solve the problem.