The error TOO_MANY_REDIRECTS can occur when accepting a quotation or editing the quotation shopping basket from the backend if you call up the backend via an unencrypted connection (http://...) but the quotation was created for a shop for which an encrypted connection (https://...) is configured by default.
In this case, please also use a secure, encrypted connection for your backend (https://... instead of http:// in the address line of the browser).
