I dont’t know about the dnssec but it does not matter if I try to renew or requesting a new cert. All are getting the same error (except for the domainame 
)
FailedChallenges: Failed authorization procedure. lekkervaren.vrouwejitske.nl (http-01): urn:acme:error:connection :: The server could not connect to the client to verify the domain :: DNS problem: SERVFAIL looking up CAA for lekkervaren.vrouwejitske.nl
I have this on several servers that already worked perfectly with Letsencrypt.