'Revise' is grayed on Supplier Response even though 'Allow response revision' is checked Negotiat

Summary:

Supplier has Accepted and submitted a response to a two stage negotiation. So the Response is Active.

Now he wants to change the response price and trying to revise the submitted Response. But the 'Revise' button is grayed out. Now he is not able to create/revise the response.

We are stuck here.

Content (please ensure you mask any confidential information):

Under Negotiation, Response Rules, we allowed the supplier for revision as follows. But still the supplier is not able to create Revision for Response.

Could anyone please check and let us know the cause of this issue?

Only 1 day left for negotiation closure. Please advise urgently.