Resolved Cannot deliver to gmail accounts - keep getting an ipv6 error

[Kwasi]

Emails to gmail seem to be the only ones that are being blocked.

I keep getting this error:

Remote server returned a response indicating a permanent error. Server Response: (550-5.7.1 [2a01:7c8:aac9:359:794e:6c1:8ca1:3fa] Our system has detected that**550-5.7.1 this message does not meet IPv6 sending guidelines regarding PTR**550-5.7.1 records and authentication. Please review**550-5.7.1 Bulk Senders Guidelines - Gmail Help for more information**550 5.7.1 . v21-v6si3427379edb.343 - gsmtp**)


I have 3 Windows VPSs at different locations all running the same exact software setups.

This particular VPS has an ipv6 address as part of its setup.

I cannot remove the ipv6 address from within Plesk.
I keep getting this error if I try to remove it:
===============
Error: Cannot remove the IP address 2a01:7c8:aac9:359:794e:6c1:8ca1:3fa because it is the last IP address present on a network interface.

Any thoughts on why gmail keeps referencing the ipv6 address and mentioning it as a reason for blocking delivery?


If I delete it from my hosting company panel, might that solve why gmail keeps referencing the ipv6 address with an Auth Error???

DNS/Reverse DNS on the 2 domains is fine.
spf is perfect.
dmarc is perfect.
dkim is a little screwy because I'm using AWS/Cloudflare, but txt/dns records at Cloudflare are not altered or intercepted in any way.


The other 2 VPSsand the domains I have there don't even have real clean spf or dmac records yet, but they all send to gmail just fine.

Major difference between those 2 VPSs and this one where I'm having all these issues is only this VPS has an ipv6 address as a part of its setup.


Thoughts???

 

[Matt R]

I had the same issue. I RDP'd into the server and just disabled ipv6 from the network adapter.

If you want to do the same, go to the network adapter list, right-click and on the correct one and select properties. In the properties window, uncheck the ipv6 box.

 

[Kwasi]

Holy Smokes!

That worked.
Emails to Gmail accounts get delivered just fine right now.
Did a test to 2 that I have, and all is a-ok so far

THANKS