Changes in Form Designer are not saved

hello dear support team

so long time i am so happy for your perfect site

now i am making some colour changes

simply at the backround colour e.g. blue

and >>> when i move to advanced options
the "advanced options" doesn't respond to any previous settings (makes reset)
and the colour is always being "reset" to white
tried many times but the "advanced options" doesn't respond to ANY changes

this happened today / yesterday and many years was all working properly

thank you in advance

Can you please share to us the Form URL you are working with.

Where-to-Find-My-Form-URL

Please make sure you click the Save buttons when doing changes thru the Form Designer.