URGENT - Forward-confirmed reverse DNS failing

[marioVP]

Our Forward-confirmed reverse DNS (FCrDNS) mechanism started rejecting Fitbit messages.

For a couple of days we've been receiving messages from the following IPs which cannot be Reversed DNS:

169.45.142.104

169.45.146.201

169.45.141.216
169.45.145.228
169.45.145.243
169.45.145.244
169.45.134.250

https://mxtoolbox.com/SuperTool.aspx?action=ptr%3a169.45.141.216#

[Gordon-C]

Hi @marioVP,

It appears the IP addresses are passing on end.  Would you confirm if you're still getting errors?  I'm trying to determine if this is temporary.

[marioVP]

Hi @Gordon-C

The problems usually start at midnight PST. We have detected this pattern in the last 4 or 5 days. At the moment it seems to be working fine, but as I said before, problem starts around midnight

[Gordon-C]

When the problem starts at midnight, how long do you receive the errors before the problem corrects itself?

[marioVP]

It lasts about 4 or 5 hours

[Gordon-C]

Would you let me know exactly what error message you are receiving?   

[marioVP]

Hi @Gordon-C

I'm affraid I don't have too much information for you. Our logs only have data like this:

getHostByAddr ENOTFOUND 169.45.145.228

Let met try to find some more info and I'll get back to you if something comes up.