You cannot synchronize with AgriBus-Web until you have finished reading the data saved in Android phone.
If there are several hundred or more work logs and fields, this loading will take a long time.
As shown in the image, if the "Synchronize data" button is grayed out and cannot be pressed,
After launching the app, wait for it to load.
If there are more than 1,000 entries, it may take about 30 minutes (depending on the throughput of Android terminal).