This description is not helpful, unfortunately.
-what do you mean by "my output is ch 1 and ch 6" ?
-how the unit is connected? Please specify which I/Os are used.
The only thing I understand is that you are trying to use a 5.1 preset (#5415) with analog outputs…and that can't be done as you'd need 6 channels, whereas the unit provides a max of 4 analog outputs.
To use the 5.1 presets you eed to load the correct routing and use digital connections like ADAT or DB-25 Aes Ebu.