Alexa nodes does not answer after few weeks


I created some nodes with the "node-red-contrib-alexa-home-skill" node and it worked fine for few weeks.

but then, in the alexa app- the red-node-nodes changed to "philipps hue" gadgets. The nodes weren't answering anymore.

Today I just added a random node-red-node without any connections, re-deplyed the flow and it worked again.

what could be the issue?
Do I really have to re-deploy my flows periodically?

thanks in advance.