Found the culprit. It was the asynchronous load of JavaScript resources in Cloudflare settings. Now when it’s off, it works. Maybe this helps someone.
Cheers
Hello Cais,
So far I’ve tried only with deactivating all other plugins. I tried also different versions of url path to gallery both in the plugin settings and adding a define in wp-config file as suggested in another similar case. I saw you requested server settings from another user with a similar issue, so here they are:
Operating System : Linux (64 Bit)
Server : Apache
Memory usage : 56.94 MByte
MYSQL Version : 5.5.41-37.0-log
SQL Mode : Not set
PHP Version : 5.4.34
PHP Safe Mode : Off
PHP Allow URL fopen : On
PHP Memory Limit : 128
PHP Max Upload Size : 50M
PHP Max Post Size : 50M
PCRE Backtracking Limit : 4194304
PHP Max Script Execute Time : 30s
PHP Exif support : Yes ( V1.4 )
PHP IPTC support : Yes
PHP XML support : Yes
Graphic Library
GD Version : bundled (2.1.0 compatible)
FreeType Support : Yes
FreeType Linkage : with freetype
T1Lib Support : Yes
GIF Read Support : Yes
GIF Create Support : Yes
JPEG Support : Yes
PNG Support : Yes
WBMP Support : Yes
XPM Support : Yes
XBM Support : Yes
JIS-mapped Japanese Font Support : No
Hoping it helps, cheers !