When uploaded file size is greater than allowed size the above message is issues
Solution
Change Nginx configuration file to allow upload of big size.
server {
listen 80;
server_name your-mayan-domain.com;
client_max_body_size 100M;
location / {
proxy_pass http://mayan:8000;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
}
}