I’m really impressed by the speed of your reactions!!

No need to hurry, I figured out what’s wrong and added the missing line in options.php.

The crash: I have no problem on my local PC XAMPP configuration. But on the hosting server, it crashes all the time I add a booking from the backoffice. I have no clue why. Here’s an extract from phpinfo, maybe you can do something with it. If I can provide other infos you may want, just let me know.

‘./configure’ ‘–prefix=/usr/local/php-7.1.1’ ‘–with-libdir=/lib64’ ‘–enable-bcmath’ ‘–enable-calendar’ ‘–enable-dba’ ‘–enable-dba=shared’ ‘–enable-exif’ ‘–enable-ftp’ ‘–enable-gd-native-ttf’ ‘–enable-mbstring’ ‘–enable-mysqlnd’ ‘–enable-pcntl’ ‘–enable-pdo=shared’ ‘–enable-re2c-cgoto’ ‘–enable-shmop’ ‘–enable-sigchild’ ‘–enable-soap’ ‘–enable-sockets’ ‘–enable-sysvmsg’ ‘–enable-sysvsem’ ‘–enable-sysvshm’ ‘–enable-wddx’ ‘–enable-zend-signals’ ‘–enable-zip’ ‘–with-bz2’ ‘–with-config-file-path=/usr/local/php-7.1.1/lib/’ ‘–with-config-file-scan-dir=/usr/local/php-7.1.1/lib/php.ini’ ‘–with-curl’ ‘–with-db1=/usr/include/db1’ ‘–with-db4=/usr/include/db43’ ‘–with-freetype-dir’ ‘–with-gd’ ‘–with-gdbm=/usr’ ‘–with-gettext’ ‘–with-iconv’ ‘–with-iconv-dir=/usr’ ‘–with-imap-ssl=/usr/local/src/imap-2007f’ ‘–with-imap=/usr/local/src/imap-2007f’ ‘–with-jpeg-dir=/usr’ ‘–with-libxml-dir=/usr’ ‘–with-mcrypt’ ‘–with-mhash’ ‘–with-mm’ ‘–with-mysqli=mysqlnd’ ‘–with-openssl=/usr/local/ssl’ ‘–with-pdo-mysql=shared,mysqlnd’ ‘–with-pdo-sqlite=shared,/usr/’ ‘–with-sqlite3=shared’ ‘–with-png-dir=/usr’ ‘–with-readline=/usr’ ‘–with-xmlrpc’ ‘–with-xpm-dir=/usr’ ‘–with-xsl=/usr’ ‘–with-zlib-dir=/usr’ ‘–with-zlib=/usr’ ‘–enable-intl’ ‘–with-icu-dir=/usr’ ‘–enable-inline-optimization’ ‘–enable-opcache’ ‘–with-mysql’ ‘–with-sqlite’ ‘–with-t1lib’ ‘ac_cv_decimal_fp_supported=no’

For whatever reason I can’t generate the error log on the hosting. Having said, the error is probably the same as in an earlier post:

https://www.e-dynamics.be/wordpress/forums/topic/an-error-occured-while-communicating-to-the-server/

One additional clue: When I click on “Printable View” of an event with bookings, I get a page with URL “http://mysite.ch/wp-admin/admin.php?page=eme-people&eme_admin_action=booking_printable&event_id=16” showing the text

IntlException thrown
Constructor failed

intl version 1.1.0 is installed on the hosting server.

I can live with localization turned off, but if you want me to dig further, let me know what else you would need.