If you installed the app in the external memory, i.e. in the microSD card and it won't load, consider installing it in the device's internal memory, because it is possible that the app itself is made to work only if installed in the device's internal memory.
Note: It is better to uninstall the app first and then install it in the internal memory.
If you don't want to uninstall the app, you can move it manually, as shown in the video demo below (varies from one device to another):
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