Magento 2 – Checkout loading is not displayed

We just had one case that after clicking “Checkout” the header, the footer and in between the rotating one “Charging sun” was shown. This continued to rotate indefinitely and the till was not displayed. After a little debugging, We then tried a rel. easy step, started Putty and the following commands…

Magento–Wrong field specified.

In a Magento 1.9 installation we had just the problem, that it was not possible to make any change in the payment. No matter what we wanted to change after trying to save always came the error message "Wrong field specified.". It did not matter, if you wanted to change the name of a payment method or enable a payment method…