What are the major barriers/ challenges during sales negotiations?

All above answers are great and came from great people and contributors, my only addition is the "over confidence" which could be an obstacle in negotiations.

- The biggest challenge is when your counterpart is not ready to listen and understand you

- Going unprepared to the negotiation

- Lack of time and patience

- Being too rigid

- Sarcasm and criticism

- Lack of confidence

- Lack of authority

I agree in all of the above answers.

In my opinion,there is many type of barriers during negotiation;

strategic, psychological, cognitive, structural and cultural. 

Most knowable,

- Die-hard bargainers.

- lack of trust.

- Dealing with saboteurs.

- Difference in gender and culture.

- communication problems / Misunderstanding.

- Over reacting & emotional responses.

                                                                              Thank You.

Building your own personal credibility is the biggest challenge in any negotiations. Besides this confidence & fear- together with poor preparation are,  in my experience,  the biggest challenges of sales negotiations. 

Thank you for the oppurtunity.

I agree in all of the above answers. In my own opinion, unknowingly negotiation may fall on different case within the process. My recent case are as follows

• Oblige to adhere the company and govrnmental policy / regulation
• Dealing with third party clients
• Dealing with objections 
• Tangible services does not comply with your clients requirement
• Failure to follow up
• Priority precautions - Revenue VS. Corporate accounts

there is nothing to say after what you answered...am full agree with you mr.ibrahim..

thank you for this useful information 

Lack of preparation, knowledge and experience.

if you don't know the USPs of your product.

Time pressure.

Lack of self confidence.

if you don't listen actively to the customer.

if you interrupt and jump to conclusions.

if you don't have win-win attitude.

Thank you.

The nature of the dealThe nature of the marketNegotiating partiesThe time factor

trust, skills, delivery of promises, convencing, continuety, profissionalism, empressions,'''''

All the pointers are correct like 

• going unprepared
• sarcasm
• jumping to conclusion etc.

but from my point of view choosing the right person for the negotiation is the main huddle you have to overcome before you start negotiation.

As if the person is not fit according to the Client / situation your negotiation is set to doom.

To avoid criticism after the deal, dealing with tough who are in wrong direction, Meeting the requirement of You boss, the legal aspects and industrial standards and to convince those who are keeping their eyes closed to say that it is darkness.