If you mean you enter the postage details and then they disappear and you have to input them again and they disappear again
there’s a thread called postage …someone else was getting this too
i reckon it’s because eBay have changed their system from yesterday …something about changing how letters and large letters are shown ..don’t ask me what they mean but anyway
they forgot to switch the oven on
if you change it to padded envelope it retains the postage
it will come up with 1.55 or something but
you can then alter the postage price to envelope rates (under where it says seller pays or buyer pays)
I believe that should be ok under the rules