3782830 - Error: "Couldn't submit your request" when submitting a Purchase Request at checkout

When I try to submit my Purchase Request at the Checkout page, the following error appears:

• Couldn't submit your request
• There was a technical issue while submitting your request. You can save your request as a draft or contact support for help with this ID: [ID]

my purchase request, internal catalog, no results, search returns no results, catalog visibility, catalog views, multiple catalog views, activated catalog, search backend, buyer search query, ariba buying search, catalog search issue, internal catalogs not showing, my purchase requests search, catalog configuration , KBA , S2P-P2O-BX-REQ , My Purchase Requests , Problem