Error 500 from Box API UI Elements Content Uploader

2 separate applications using the Box API - UI Elements - Content Uploader worked for weeks and now both fail with error 500. Each app uses its own token and uploads files to a different box folder. This afternoon the upload was hit and miss.. sometimes worked on 3rd or 4th click. Now it's just permanent 500 internal server error.

Both applications have proper access to folders and active access tokens.

UPDATE: Even the demo on CodePen now fails with Error 500: https://developer.box.com/guides/embed/ui-elements/uploader/

Please advise. Box API status shows green, hmmmm.

Response: {"type":"error","status":500,"code":"internal_server_error","help_url":"http:\/\/developers.box.com\/docs\/#errors","message":"Internal Server Error","request_id":"fy21cxgk62ddzvta"}

Request headers:

application/json

Accept-Encoding	gzip, deflate, br
Accept-Language	en-US,en;q=0.5
Authorization	Bearer XXXXX-token-deleted-for-privacy-XXXXX
Connection	keep-alive
Content-Length	84
Content-Type	application/json
Host	api.box.com
Origin	http://localhost:8081
Referer	http://localhost:8081/add
User-Agent	Mozilla/5.0 (Macintosh; Intel …) Gecko/20100101 Firefox/68.0
X-Box-Client-Name	ContentUploader

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