XF 2.2 Very strange problem in new standardstyle Modern

[Abraham54]

I introduced a new standard style on my forum, Modern.
Additionally there are two Modern Dark styles and e gray Modern style.

Modern, as new standard style has a very strange problem - bold fonts are not possible.
All other Modern styles do not have this problem.

I decided to make Modern2 out of Modern Grey Fore.
This style functioned with bold fonts.
But: after changing Header and navigation to the colors of Modern, Modern2 had the same problem as Modern, bold fonts not possible.

I do not understand this.

 

[Abraham54]

I have asked my host to enable proc_open in PHP.

 

[Abraham54]

My host says proc_open is active, but in PHP on my server no proc-open