Node red: Error: getaddrinfo EAI_AGAIN

ı use PushOver and Whatsapp to sent notifications from node red in ihost.
this works well however after a few days the notifications are not sent anymore and both Whatsapp and pushover nodes give this error: Error: getaddrinfo EAI_AGAIN
after restarting node red on the ihost (docker) it starts working again for some days. this without changing anything in the node red flow.
does any of you all know how i can prevent this error?