Guest check out error

[kinganurag]

wHEN I FILL BILLING AND SHIIPING DETAILS AND click next 
It shows error on one page checkout page


TECHNICAL ERROR: unable to save adresses Details: Error thro wn: [object Object] Text status: parsererror


I have also attached screen shot any one have any idea
when i check console it is showing
 

[Deprecation] Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user's experience. For more help, check https://xhr.spec.whatwg.org/.

send @ v_21_cd65044c6628717634aa175484f0593b.js:4