Unable to upload a file to a remote ftps server

This usually happens when the server you are trying to connect to does not like the protocol or cipher.

1. Try using sslv2

   curl --sslv2 --connect-timeout 90 -T nishant.txt  ftps://ftp.box.com/RANDOM_FOLDER/nishants.txt --user "username:password" -x socks://internal-proxy-elb-7288384.eu-central-1.elb.amazonaws.com:1080 -v

2. You could be trying to connect to the site using an ssl cipher that the site is configured to reject.Try using curl with --ciphers ALL option. Also, try testing an openssl connection

   openssl s_client -connect ftp.box.com:990

   openssl s_client -connect ftp.box.com:990 -ssl3

3. The results of the above commands may also indicate whether this is a bug with curl or not. You could try to downgrade curl to 7.33.0-3.

Edit 1

I tested the remote site using openssl commands. It seems SSL2/3 is not supported. You need to use TLSv1 with ciphers DES-CBC3-SHA.

Try this

curl -1 --connect-timeout 90 -T nishant.txt  ftps://ftp.box.com/RANDOM_FOLDER/nishants.txt --user "username:password" -x socks://internal-proxy-elb-7288384.eu-central-1.elb.amazonaws.com:1080 -v

If you receive the same error, try specifying the ciphers mentioned above using --ciphers option.