Self-hosted sites lack Separator lock color options and other settings

[alinclamba]

Description

The color option for the Separator block is missing in the new experimental editor. Users are unable to change the separator's color, even though the option appears briefly first time before disappearing, and then never appears again. I was able to replicate the issue on self-hosted sites but does not occur on Atomic sites. Other blocks, such as Heading and Button, allow color changes when the Gutenberg plugin is enabled.

This was initially reported in Slack: p1738777146524439-slack-C0180B5PRJ4

Step-by-step reproduction instructions

On a self-hosted site:

1. Insert a Separator block.
2. Click the settings icon to access the block customization options.
3. Observe that the color option may appear briefly for the first time but then disappear.
4. Notice that the color option is not displayed anymore after that even if you close/re-open the app.

Expected behaviour

The color option for the Separator block should be available and allow users to modify the block’s color.

Actual behaviour

The color option is missing from the the Separator block.

Screenshots or screen recording (optional)

1. The color option for the Separator block appears briefly for the first time, but then disappears and never appear again.
2. From my tests, the issue occurs on self-hosted sites but not on Atomic sites.
3. Installing and enabling the Gutenberg plugin does not resolve the issue.
4. Other blocks (e.g., Heading, Button) allow color customization when the Gutenberg plugin is enabled.

WordPress information

• WordPress version:
• Gutenberg version:
• Are all plugins except Gutenberg deactivated?
• Are you using a default theme (e.g. Twenty Twenty-One)?

Device information

• Device: iPhone 13
• Operating system: iOS 18.2
• Jetpack app version: 25.7.1
• WordPress themes tested: Divi and Twenty Twenty Four
• Gutenberg plugin: 20.2.0

[dcalhoun]

As noted in wordpress-mobile/WordPress-Android#21700, this appears to originate from failed authentication of API request for self-hosted sites. It results in several missing editor settings and features—colors, theme styles, etc.

I believe the incorrect site API root URL and/or authentication header is used for self-hosted sites.