I gave up on this site since I lost 15 in a row on 1.5 (63,33%)
15 in a row on 1.5x is harsh but not impossible to get
I got 14 in a row on a regular 1% house edge sites multiple times,never a 15 in a row though
this is how the chances to roll it look like:

basically you have a good chance to roll it once every 10.000.000 rolls or so