audio/strawberry: Could not load the Qt platform plugin "xcb"

Hello,

When I start audio/strawberry (strawberry-qt6-1.0.21_1) I get the
following error:

$ strawberry --verbose
10:54:59.290 INFO  main:180                         Strawberry 1.0.21 Qt "6.6.0"
10:54:59.291 INFO  main:181                         "FreeBSD 14.0-RELEASE 14.0 - (freebsd 14.0-RELEASE) [x86_64]"
10:54:59.308 WARN  unknown                          could not connect to display  
10:54:59.308 DEBUG unknown                          Could not load the Qt platform plugin "xcb" in "" even though it was found. 
10:54:59.308 ERROR unknown                          This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem. 
10:54:59.308 ERROR unknown                           
10:54:59.308 ERROR unknown                          Available platform plugins are: minimal, offscreen, vkkhrdisplay, vnc, xcb. 
10:54:59.308 ERROR unknown                           
Abort trap (core dumped)

Google offers various advice for people using Linux or Windows; would
you please advise what's the correct fix here?

-- 
Janos Dohanics