Go into the assignment and toggle of the 3rd party read-only switch off. Then you can edit or delete the assignment. Toggle it back on in order to continue syncing with canvas. 

Go in and edit the assignment group under the canvas side, then try editing one of the grades for a student. (For example I graded a student entry that was turned in late.) Then I tried resyncing the ...

I accidentally synced an assignment to synergy under the wrong assignment group. Now I cannot edit the assignment in synergy or delete it. I have tried editing the assignment group on both the synergy...

Once you change a grade using the speed-grader it will let you resync!  I just graded a late entry and tried to resync to see if it would and it corrected the problem. 

No. I am still trying to figure it out. 

Go into the assignment and toggle of the 3rd party read-only switch off. Then you can edit or delete the assignment. Toggle it back on in order to continue syncing with canvas. 

Go in and edit the assignment group under the canvas side, then try editing one of the grades for a student. (For example I graded a student entry that was turned in late.) Then I tried resyncing the ...

Once you change a grade using the speed-grader it will let you resync!  I just graded a late entry and tried to resync to see if it would and it corrected the problem. 

No. I am still trying to figure it out. 

I accidentally synced an assignment to synergy under the wrong assignment group. Now I cannot edit the assignment in synergy or delete it. I have tried editing the assignment group on both the synergy...