Alpha MK2 problem with power loss

Good morning.

I have an Alpha MK2 20W laser, which is great.

It’s less than a year old and has had little use.

However, it’s visibly showing a problem with power loss.

I tested it and confirmed that it doesn’t cut like it did when I bought it.

I’ve already checked everything and changed the lens, but it didn’t solve the problem.

What could it be?

How can I fix it?

Thank you.

Jackson