AEM 6.3 is shipped with a known product bug that causes translations of pages with experience fragments to fail.
This issue is resolved in AEM 6.3.1 (SP1, "Service Pack 1"). Install AEM6.3 SP1 from:
Another known cause of this issue is when the translation configuration is missing the experience fragment resource type. To fix this issue, follow the steps below:
- Open a browser to the author instance URL and log in as an administrator.
- Click Adobe Experience Manager > Tools > General > Translation Configuration.
- Select the check box next to /content and click Edit.
- Click References.
- In the Resource Type field, enter "cq/experience-fragments/editor/components/experiencefragment".
- In the Reference Type field, enter "fragmentPath".