SSL certificate not valid because wildcard doesn't match subdomain with hyphen?

I have a domain like this: https://abc-.domain.com/. If I open this site different browser are showing me different results. E.g. Firefox throws the error security risk. Chrome on the other side loads the site without issues.

If I call the domain https://abc.domain.com the site is opened in Firefox without issues. So the only difference I can see is the hypen -.

The certificate should be valid for the following subdomains/domains:

*.domain.com, domain.com

I tried to verfiy the certificate with openssl s_client -debug -connect abc-.domain.com:443 and can't find something wrong.

So is the hyphen not a valid wildcard character?

As detailed by @SteffenUllrich in the comments, hostnames may contain a hyphen-minus (-) but this character may not appear either at the beginning or end of a hostname e.g.:

ex. Correct use of -

sub-domain.example.com

ex. Incorrect use of -

-subdomain-.example.com

The cited Wikipedia article provides a direct link to RFC 952, which states:

A "name" (Net, Host, Gateway, or Domain name) is a text string up to 24 characters drawn from the alphabet (A-Z), digits (0-9), minus sign (-), and period (.)

And regarding your particular case:

The last character must not be a minus sign or period.