Edited map issues - or the game crashing when uploading a map - could be due to many different reasons. Namely:
- Your Steam account cannot be limited. Read more here;
- You have to accept the latest Workshop EULA here;
- You can hit the per-player upload limit in case you have already submitted tons of maps;
- The map you are trying to upload has some issues with its files (no preview, bad description, bad naming, or such);
- Firewall settings or internet connection issues. A player in the past has mentioned that white-listing the IP helped him solve it, too (Steam FAQ)