@celesteh  Maybe can try ;

1. stop the daemon (if you have it) /scripts/stopdaemons.sh
2. check DB error /scripts/checkschema.php (but it must be done at end of the upgrade)
3. scripts/clean_file_table.php -y
4. scripts/delete_orphan_files.php -y
5. scripts/remove_duplicate_file_urls.php -y
6. plugins/OStatus/scripts/fixup-shadow.php
7. scripts/fixup_deletions.php
8. plugins/OStatus/scripts/update_ostatus_profiles.php -a
9. ostatus/scripts/upgrade.php
10. restart daemon scripts/startdaemons.sh

Then you check whole system ? !gnusocial