HELP required

can you please advise why i get this message when uploading a simple line sketch

Vectorizing failed: InvalidSignatureException: Signature not yet current: 20180818T021334Z is still later than 20180818T021224Z (20180818T020724Z + 5 min.). Try re-uploading the image or refreshing your browser.

Seen that issue before.
Closing your browser and reopening.
Check the time on your PC
Restart your PC