weapon +16 ? help pls

ich hab meine waffe +16 gemacht als ich nochmal upgraden wollte ist es fehlgeschlagen und +15 geworden..
wie kann ich das preventieren ?

english vers:
I've made my weapon +16 but after trying to craft it again it went back to +15
is there any way to prevent that ?

hilfe wird meine einem grossen danke belohnt :handsdown:

btw I play on Milanlz and I dont have laggs anymore so the server changed kinda o.o

Purchased stones and enchantments that luck be with you

only that ?
that would rly suck O.O

I have the same problem, please someone tell how to improve my patch of love, medal, and still does not come after hundreds of trials. p.s I play on private server