Not to be unkind, but that cable end looks horrible. Did you strip by hand? I, of course, don't know what's available in your country but you need a stripper.
Here is a good page with photos showing the process. Note how clean the cuts are. The page shows a single conductor center but my cable had twisted and it fit the connector just fine; you don't need to twist it if it doesn't already have a twist.
I would like to add a couple of notes because the RG59 strippers can be used for RG400 cable but you have to make some adjustments. An RG59 stripper will leave too much center conductor exposed and not enough center insulation exposed. After stripping, slip a center connector over the conductor and see how much conductor remains exposed (don't push the connector down to the insulation; it should slip easily on and stop about 1/8 inch short). Remove the connector and trim the conductor by that much using flush cutters; you may have to carefully pinch the end of the conductor to get it to fit back into the connector. Once the connector sits easily on the insulation, crimp it.
Now slide on the body (I really hope you remember to put the sleeve on the cable
before you strip; like the sleeve for fluid flare fittings, I always seem to forget) and see how short the center connector comes up (again, don't force it; just insert it until the base is stopped by shielding and outer insulation). It needs to be approximately flush with the body, so you will need to strip that additional amount from the outer shielding. You can do that with a razor blade or X-Acto knife if you're careful not to cut the shielding, but I just got a second stripper and removed all the blades except for the one for the outer conductor. You can find these strippers for under $10US online. When you've removed enough insulation, the center connector will 'click' into place in the body.
Now, push the shielding up along the body and you will see that it's too long. It's not critical as long as it's long enough to be trapped between the sleeve and body to make a good connection, so take your flush cutters and trim it down. When it's short enough for the sleeve to completely cover it, push the sleeve into place and crimp. You're done.
It sounds like a lot of work but I found that only the first one was difficult. After that, I had an idea how much to trim and could do it without all the steps of test fitting. A mulitmeter is useful to test your connectors; you should not have continuity between center connector and body but the connectors at both ends should have continuity body-to-body and center-to-center.
