Error: SMBCLIENT is not installed

How to solve such a problem.
I hope some friends can help me out. Thank you

Hi kiwi_G. it’s hard to read the error message you’ve marked red in your screeenshot. perhaps you translate it?

As mentioned in de docs:
https://docs.nextcloud.com/server/17/admin_manual/configuration_files/external_storage/smb.html

For improved reliability and performance, we recommended installing libsmbclient-php , a native PHP module for connecting to SMB servers.

On debian or ubuntu that would be:
sudo apt install php-smbclient