Stain blocker for stone

[CrazyFool]

Hi guys

Please can you help me diagnose this problem?:
https://drive.google.com/folderview?id=1Ab_8DpBVzlzVBz2Zcw4WdGZTy3wXkUC7
Not sure what sort of stone it is, but I painted it using masonry paint last summer and it was ruined within a few weeks.
I need some sort of stain blocker before I hit at it again with masonry paint.

Kind regards

CF

 

[KenGMac]

Might be me, but?

Is it possible that the staining occurs where the paint you have applied has peeled and allowed rain water to get behind your paint causing the staining??

I Zoomed in on the images posted, and it appears that there are paint cracks in [most] of the paint finish above the areas of staining?

Can I suggest an up close look to see if indeed blistering / bubbling / crack has occasioned the stains?

Ken