Special Character Plugin Not Found – 500 Internal Error

i do not really know what you might think this plugin does. If it is only to insert a html entity that could not be seen – it is not neccessary.
you can insert &nbsp ; without that space ( between p and semicolon ) – and you will have a invisible heading there – where you can insert your logo either as pseudo-container background like here: https://webers-testseite.de/tesla/
you see that i did it a bit different – you can make this heading invisible by font color : transparent ( i let it at opacity 0.1)
or set the text-indent to a big value ( -2000px). the advantage would be a SEO one – because there is a heading f.e. Tesla Logo then.
i gave a custom class to the slider: tesla

.tesla .slide-1 .avia-caption-title {
    color: rgba(255,255,255,0.1);
}

.tesla .slide-1 .avia-caption-title::before {
    content: "";
    width: 100px;
    height: 100px;
    position: absolute;
    left: -60px;
    top: -60px;
    background-image: url(/wp-content/uploads/TESLA-logo.png);
    background-repeat: no-repeat;
    background-size: contain;
}

or – you replace the content directly with the image:

.tesla .slide-1 .avia-caption-title {
    content: url(/wp-content/uploads/TESLA-logo.png);
}

if this will work on all browsers – i don’t know
This above is only for slide-1 – if this should be for all slides – let that class out from the css code

yes: this is not a warning that you have activated the self-destruction button : it might break !

Warning: Characters <,>,[,] might break ALB backend or frontend. Read more if you want to use them. You can use valid HTML markup.

And you see in detail what characters could indicate that. – those which are correlated with code ( tags etc. )

i see your logo on your page – does it break your layout ??? – no – so ?
it might – conditional case
As i said above – this is not a selfdestructing information – try it – if it works – good – if not change it.