How to solde error

Hello Guys, i need you help
i’ve this error on nextcloud

How can i solve this please ?

PHP Startup: Unable to load dynamic library ‘’ (tried: /usr/lib/php/20180731/ (/usr/lib/php/20180731/ undefined symbol: mbfl_convert_filter_flush), /usr/lib/php/20180731/ (/usr/lib/php/20180731/ cannot open shared object file: No such file or directory)) at Unknown#0

Please use the support template… Otherwise we can only guess what your environment is like…

@m.diagne @Chartman123
Yes we need more infos e.g. the operating system and version. Also if you use the normal php packages or not. Maybe this helps you. Make a backup before making any changes.