You can fix this temporarily by deleting the session files, but the long term solution is to get more space for your server. You've run out. How many session files do you have in there? What else does your site store? Image uploads? Its strange to see a site go over their quota by sessions alone, but it's possible. What is the oldest session file date? Perhaps somethings not working properly as older sessions should be cleared out periodically and automatically by php itself (not laravel)
What I'd do is just delete all session files older than something like 5 days. That shouldn't affect any current users, but that depends on your session settings for how long they last.
find /home/laravel1/public_html/storage/framework/sessions -mtime +5 -type f -delete
That will delete all files in the sessions dir older than 5 days. You can adjust the number of days by changing the "+5".