Wall plaster is crumbling - What should be done?

Hello everyone, I once again need the help of this great forum and already say thank you!

We wanted to preserve a red, old brick wall and had it replastered.
Here first is the picture of the old wall:



We painted the plastered wall. On a longer section (see the following photos), after one year, paint and partly plaster are now coming off.





If we now repair the wall at the damaged spots (plaster) and then repaint, we will probably have the same problem again after the next winter. Does anyone have a tip on what we can do here?

THANK YOU!

Best regards Daniel

What was used for plastering? 30 characters

Hello Guckuck2!

I’m honest: I don’t know... I can only say that the original wall behind the plaster had really aged and had absorbed some water from the ground. If this info helps somehow...

Of course, many things could have gone wrong. Wet wall, missing bonding agent, wrong plaster, all the way to the wrong paint.