When you use a phone case, its thickness can prevent your phone from being correctly docked. Thus, charging is not done correctly or not done at all.
If you are stuck in this situation, you may need to pay attention to the way your NVX 200's phone adapter and cradle are set.
As illustrated below on illustration 2, you can set the phone cable adapter to 2 different positions. If you use a phone case you will want to set it to the highest position.
To set the cable to the highest position, you will need to position the cable into the adapter in the right position before inserting the whole adapter+cable into your NVX 200. Once the adapter is inserted in the NVX 200, it is locked and the phone cable will stay in the defined position.
Please also pay attention to the way you assemble the cable and the adapter. As showed with illustration 1, the two small bumps on cable's head must be aligned with the smaller tab of the adapter.
You can find at the end of this article a video showing the whole process.
Here is a detailed video showing the whole process: