Can't get Blackmagic Ultrastudio HD Mini to work

Hi, first time user of CasparCG. I’m trying to use my Ultrastudio HD mini card, but get the following error in server logs:

[struct caspar::tag_msg_info *] = UltraStudio HD Mini [1-1|720p5000] Could not enable fill video output.

Here’s my config:
>

<channel>
    <video-mode>720p5000</video-mode>
    <consumers>
        <decklink>
            <device>1</device>
            <embedded-audio>false</embedded-audio>
            <channel-layout>stereo</channel-layout>
            <latency>normal</latency>
            <keyer>external</keyer>
            <key-only>false</key-only>
            <buffer-depth>3</buffer-depth>
            <custom-allocator>true</custom-allocator>
        </decklink>
    </consumers>
</channel>

My Atem Ultrastudio is set to 720p50 in Decklink video software. Anyone know whats causing this error? Not getting picture on Ultrastudio from Caspar.

Have you tried with setting:

<keyer>default</keyer>

Does that give you any picture?

Still no picture with

<keyer>default</keyer>

More from the log:

[2018-12-13 14:14:55.694] [9664] [info] video_channel[1|720p5000] Successfully Initialized.
[2018-12-13 14:14:55.764] [10192] [info] UltraStudio HD Mini [1-1|720p5000] Using custom allocator.
[2018-12-13 14:14:55.773] [10192] [debug] UltraStudio HD Mini [1-1|720p5000] allocated a total of 0 bytes and was called 0 times during playout
[2018-12-13 14:14:55.781] [9664] [error] consumer\decklink_consumer.cpp(293): Throw in function void __thiscall caspar::decklink::decklink_consumer::enable_video(enum _BMDDisplayMode)
Dynamic exception type: class boost::exception_detail::clone_impl
std::exception::what: Unknown exception
[struct caspar::tag_msg_info *] = UltraStudio HD Mini [1-1|720p5000] Could not enable fill video output.

A restart solved it. So config was correct, but I assume some settings to the Blackmagic box were not active before I restarted.