KMix crashes on startup

In an attempt to find a workaround for #298 (closed) I tried to use KMix, but it crashes on startup:

#0  0x00007ffff006765a in create_server.constprop.0 (protocol=protocol@entry=0x5555559b1ad0, core=0x555555883840, props=<optimized out>) at ../pipewire/src/modules/module-protocol-native.c:1063
1063            pw_loop_add_hook(pw_context_get_main_loop(context), &s->hook, &impl_hooks, s);
        _f = 0x1be3d743f
        _o = 0x7ffff7df04c0
        this = 0x555555868bb0
        context = 0x5555559d8eb0
        s = 0x555555868bb0
        __func__ = <optimized out>
#1  0x00007ffff00532ec in pipewire__module_init (module=module@entry=0x5555559e0080, args=args@entry=0x0) at ../pipewire/src/modules/module-protocol-native.c:1235
1235            d->local = create_server(this, context->core, &props->dict);
        context = 0x5555559d8eb0
        this = 0x5555559b1ad0
        d = 0x5555559b1b48
        props = <optimized out>
        res = <optimized out>
        __func__ = "pipewire__module_init"
#2  0x00007ffff4aee629 in pw_context_load_module (context=0x5555559d8eb0, name=0x7fffffffd340 "\b\001\236UUU", args=0x0, properties=0x0) at ../pipewire/src/pipewire/impl-module.c:249
249             if ((res = init_func(this, args)) < 0)
        this = 0x5555559e0080
        impl = 0x5555559e0080
        hnd = 0x0
        filename = 0x0
        module_dir = <optimized out>
        res = <optimized out>
        init_func = 0x7ffff00530f0 <pipewire__module_init>
        __func__ = "pw_context_load_module"
#3  0x00007ffff4ad7749 in load_module_profile (profile=0x5555559e2350 "default", this=0x5555559d8eb0) at ../pipewire/src/pipewire/context.c:322
322             load_module_profile(this, str);
        str = <optimized out>
        state = 0x5555559e2357 ""
        len = 7
        str = <optimized out>
        state = <optimized out>
        len = <optimized out>
        __func__ = <optimized out>
#4  pw_context_new (main_loop=main_loop@entry=0x555555882f20, properties=<optimized out>, user_data_size=user_data_size@entry=320) at ../pipewire/src/pipewire/context.c:322
322             load_module_profile(this, str);
        impl = 0x5555559d8eb0
        this = 0x5555559d8eb0
        lib = <optimized out>
        str = 0x5555559e2350 "default"
        dbus_iface = 0x5555559be580
        n_support = <optimized out>
        pr = <optimized out>
        cpu = <optimized out>
        res = -11296
        __func__ = "pw_context_new"
#5  0x00007ffff5c9d7b5 in pa_context_new_with_proplist (mainloop=0x555555882f20, name=0x7ffff7df9709 "KMix", p=<optimized out>) at ../pipewire/pipewire-pulseaudio/src/context.c:1651
1651            context = pw_context_new(loop,
        context = <optimized out>
        loop = 0x555555882f20
#6  0x00007ffff7de57b8 in ?? () from /usr/lib/libkmixcore.so.5
No symbol table info available.
#7  0x00007ffff7de87aa in ?? () from /usr/lib/libkmixcore.so.5
No symbol table info available.
#8  0x00007ffff7de8b97 in ?? () from /usr/lib/libkmixcore.so.5
No symbol table info available.
#9  0x00007ffff7dc52ea in Mixer::Mixer(QString const&, int) () from /usr/lib/libkmixcore.so.5
No symbol table info available.
#10 0x00007ffff7dbe8e1 in ?? () from /usr/lib/libkmixcore.so.5
No symbol table info available.
#11 0x00007ffff7dbfd83 in MixerToolBox::initMixer(bool, QStringList const&, bool) () from /usr/lib/libkmixcore.so.5
No symbol table info available.
#12 0x000055555557d0be in ?? ()
No symbol table info available.
#13 0x000055555557fdf1 in ?? ()
No symbol table info available.
#14 0x00005555555805a2 in ?? ()
No symbol table info available.
#15 0x0000555555580741 in ?? ()
No symbol table info available.
#16 0x0000555555573a75 in ?? ()
No symbol table info available.
#17 0x00007ffff63ae152 in __libc_start_main () from /usr/lib/libc.so.6
No symbol table info available.
#18 0x0000555555573cae in ?? ()
No symbol table info available.