Issue:
Trying to export galleries and seeing this error in the admin header (not log)
Warning: /var/export/gallery/Album_20201109131959.csv): failed to open stream: No such file or directory in /home/justinb/public_html/vendor/magento/framework/File/Csv.php on line 154
Solution:
The root of the issue is that the folder /export/gallery does not have permission to create files.
To solve the issue, please change two files:
app/code/Bss/Gallery/Controller/Adminhtml/Export/ExportCategory.php
app/code/Bss/Gallery/Controller/Adminhtml/Export/ExportItem.php
Please replace two files on the site and flush the cache.
If you need any help, please feel free to contact us.