Not Able to do "Apply Config" - Error: Reload failed because retrieve_conf encountered an error: 255

I am new to the IP-PBX domain.. After installing PBX for 1st time. Getting below error.

Looking for the expert help to resolve the issue..

Reload failed because retrieve_conf encountered an error: 255

exit: 255
Unable to continue. Error with the templating engine: array_merge(): Argument #2 is not an array:: in /var/www/html/admin/libraries/utility.functions.php on line 207

#0 /var/www/html/admin/libraries/BMO/Less.class.php(209): die_freepbx('Error with the ...') #1 /var/www/html/admin/libraries/BMO/Less.class.php(94): FreePBX\Less->getCachedFile('/var/www/html/a...', '/admin/assets/c...', Array)

#2 /var/lib/asterisk/bin/retrieve_conf(173): FreePBX\Less->generateModuleStyles('conferences')

#3 /var/lib/asterisk/bin/retrieve_conf(551): connectdirs->generate_less('conferences')

#4 {main}