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Error:
Layers generation - Bad texel mapping for surface mask image (468.75x468.75).
Means your satellite texture/mask resolution is different what you write in Mapframe properties → samplers → Satellite/Surface (mask) source images. Make sure the resolution is the same as in your images.
In more detailed example, if you wrote into mapframe: 10240 but in fact your actual satellite texture/mask bitmap BMP image(s) are 20480, this would cause that above error.