This is normal. The customer is comparing prices, and he has quoted prices to several manufacturers at the same time. After comprehensive comparison, you can try to explore their estimated prices, and show your company's competitive advantage more when quoting, and maybe you will win.
If the quotation fails many times, it shows that the customer is not sincere enough and can consider giving up.
There is also a situation where peers come to test your price, and this situation should be dealt with as soon as possible.