Batch submission does not reflect more than 3 sites

Site A (MainWP Child)
Site A (MainWP Child)
Site B (MainWP Child)
Site C (MainWP Child)
Site D (MainWP Child)
Site E (MainWP Child)

We began checking operations at

When I try to submit a batch from the admin-only site, A, B, and C are OK to submit, but D and E show the following error: "A, B, and C are OK to submit, but D and E are not OK.
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[Domain name] : MainWP Child plugin not detected or could not be reached! Ensure the MainWP Child plugin is installed and activated on the child site, and there are no security rules blocking requests. If you continue experiencing this issue, check the MainWP Community for help.

If I try and submit to D,E from the admin site, it submits without any problem.
Any ideas for a solution would be appreciated.
Sorry for my poor English.

Hi @s.kikuchi-alpha

Would you mind opening a private Help Desk ticket so we can collect some additional information & investigate further?