@mouseart Custom vision portal had some known issues earlier this week. Which are now resolved. Please try to open the portal again and you should be able to login successfully if you have access.
Similar issues:
https://learn.microsoft.com/en-us/answers/questions/742929/customvisionai-whoops-we-can39t-seem-to-find-the-p.html?childToView=744351#comment-744351
https://learn.microsoft.com/en-us/answers/questions/742944/index.html
https://learn.microsoft.com/en-us/answers/questions/742999/index.html
https://learn.microsoft.com/en-us/answers/questions/744686/cannot-access-httpswwwcustomvisionai.html
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