After clicking 'place order' I am not redirected to Shape Shift to make the payment. Instead, it gives a spinning progress indicator for a few seconds, then a blank error:
[2018-05-06 02:46:01] main.INFO: API START [] []
[2018-05-06 02:46:02] main.INFO: SELECT CURRENCY NAME: Litecoin [] []
[2018-05-06 02:46:03] main.INFO: DEPOSIT ADDRESS: LfEM5mhtRYVsemV16G3xaM55hH5WZg2uUW [] []
[2018-05-06 02:46:03] main.INFO: RETURN ADDRESS: [] []
[2018-05-06 02:46:03] main.INFO: AMOUNT: 0.0557289345 [] []
[2018-05-06 02:46:03] main.INFO: API XCHECK DEFAULT [] []
[2018-05-06 02:46:03] main.INFO: API XCHECK AMOUNT [] []
[2018-05-06 02:46:03] main.INFO: sendFixedAmount() 1 [] []
[2018-05-06 02:46:03] main.INFO: sendFixedAmount() 2 [] []
[2018-05-06 02:46:03] main.INFO: sendFixedAmount() 3 [] []
[2018-05-06 02:46:21] main.INFO: sendFixedAmount() DATA: {"success":{"orderId":"7d4ac5ce-e595-4080-ba83-8d262cce6c46","pair":"eth_ltc","withdrawal":"LfEM5mhtRYVsemV16G3xaM55hH5WZg2uUW","withdrawalAmount":"0.0557289345","deposit":"0x8ea24bd7de96e74cba59ab7b4d52432f3a893463","depositAmount":"0.0123313","expiration":1525575381542,"quotedRate":"4.58012726","maxLimit":6.01255456,"returnAddress":"","apiPubKey":"2106861f10516dabde38412e6568a11890605ccea018377daf8fa4378eeed12f33a7b73bda9ed23250fbbedf939e5101be80218746ac97edca6ab96516d92f73","minerFee":"0.00075"}} []
Order goes through fine if I choose a different payment method.
Magento v2.2.3