WCS: server fails with a small coverage

[Jos é Vte Higón]

Hi,thanks for yours answers.
We are investigating about this problem.Our client must treat this issue.

But... why doesn't work MAXSCALE?
This is the mapfile:

MAP
        NAME 'prueba_wcs'
        EXTENT 742806.4 4264938.3 753600.4 4268018.3
        DEBUG ON
        IMAGETYPE PNG
        #IMAGECOLOR 0 0 0
        UNITS METERS
        OUTPUTFORMAT
        NAME GEOTIFF_INT16
                DRIVER "GDAL/GTiff"
                IMAGEMODE INT16
                EXTENSION "tif"
        END

WEB
    TEMPLATE "."
    MAXSCALE 1000000
    METADATA
      "wcs_label" "Servidor pruebas wcs"
      "wcs_keywordlist" "WCS"
      "wcs_onlineresource" "http://gruposigp2/cgi-bin/wcs"
    END
    LOG "/usr/local/mapserver/wcs.log"
    IMAGEURL "/usr/local/mapserver/tmp/"
    IMAGEPATH "/usr/local/mapserver/tmp/"
END

PROJECTION
        "init=epsg:32630"
END
LAYER
    NAME "quickbird3"
    STATUS ON
    TYPE RASTER
    PROCESSING "SCALE=AUTO"
    PROCESSING "BANDS=1,2,3"
    UNITS METERS
    MAXSCALE 500000
    METADATA
      wcs_name "quickbird3"
      wcs_label "Quickbird R2C2"
      ows_srs   "EPSG:32630"
      ows_extent "742806.4 4264938.3 753600.4 4268018.3"
      wcs_resolution "0.7 0.7"
      wcs_formats "GEOTIFF_INT16"
      wcs_nativeformat "raw_binary"
      wcs_rangeset_axes "bands"
      wcs_rangeset_label "bands"
      wcs_rangeset_name "bands"
      wcs_bandcount "3"
    END
    PROJECTION
        "init=epsg:32630"
    END
    DUMP TRUE
    DATA '/home/data/quickbird/221_r2c2_zona.tif'
END
END #map