Error/ Warning for one Configuration

Dear Duplicati Community,

i have four different folders added to backup with Duplicati. All are configured with similiar/same standard parameters: Folder with all files (nothing excluded), connection via webdav, intelligent backup deletion.
One of these four folders return a error everytime the config runs (i already deleted the folder, added it again and installed also a clean version of duplicati). I attached my error log. Does anyone know whats wrong?

solved: on Mac: Missing certificates