Click the File ==> Open option, where you will find the reason why you are not able to open your lab. If you see multiple assignment files saved, then delete all those and get a fresh copy and then re-submit.
Also make sure to save a copy of one file with the lowest memory if it is possible for your reference in your local computer, to know why the issue occured.
Once you have deleted the assignment files, also make sure to delete browser and cache history.
Then Re-login, and to get a fresh copy
- Click File==> Open, select all the files and then delete. You will notice 404 error on screen.
- Now on the top right corner side Click
, then reboot. Once rebooting done. - Click again, click Get the latest version, then Update Lab. You will have a fresh copy of the assignment. Re-Do the assignment.
To avoid such error again, avoid too many or unnecessary print statement left in the assignment. avoid adding codes outside of ###START AND 3ND CODE HERE###
Avoid adding or editing or deleting of cells
Let me know if issue still persist.
Regards
DP