You're asking how to submit the requested organization documents when the failed validation shows no upload option, and whether the validation can be reopened.
The Artifact Signing FAQ, under "What if Organization identity validation fails?", covers this directly:
"In cases where extra documents were required, you have exhausted all three attempts. Therefore, we can't proceed further with the onboarding."
That's the documented reason the upload control isn't appearing — it isn't a portal fault specific to your tenant.
On reopening the validation: nothing in the documentation describes reopening a failed organization validation, so I wouldn't plan around that happening.
A new request may still be worth submitting, for two specific reasons.
On a parallel thread with the same failure, Meha-MSFT (Microsoft employee) answered: "create another request with no free host domains in email addresses." If the primary email on your request is on gmail, outlook.com or similar rather than your organization's own domain, that's worth correcting before you try again. The FAQ separately notes the address shouldn't be a distribution list, and must be able to receive links from external senders.
Second, if the failure actually came from a missed email verification link rather than a documents decision, the FAQ says to create a new request — that link expires after seven days and can't be resent on the same one. Worth establishing which of the two you hit, since the remedies differ.
If Microsoft emailed you requesting the documents, reply on that thread. It's a known Microsoft sender, so there's no exposure risk, and it reaches the team that made the decision. Keep your Identity Validation ID to hand for that reply — but don't post it here, and don't send documents anywhere else.
One thing to be aware of on the support side: the asker on that parallel thread opened a case under Basic support with his document attached and received an automated reply saying it required paid technical support.
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