Same as @JardeRich , @nhughes and @poke50uk Using German related mail services.
These blacklists are becoming very annoying.
Why is the German SMTP server so often blacklisted and the US SMTP server not?
I assume that the same configuration is used.
I do see that US is based on upstream Leaseweb and the German equivalent on Linode.
Why not also the German SMTP servers on Leaseweb?
I have recently had more mail servers on Linode and blacklists are unfortunately very common. And unfortunately it is not only Microsoft that blacklists for almost nothing. (Also unjustifiably so). Apparently Linode's IP block has a very bad reputation and little needs to happen for another blacklist to appear.
Because nowadays mail from the big 3 (Google. Microsoft and Amazon) functions strongly on the basis of IP reputation and reputation in general.
Hopefully there will be a permanent solution. Thank you for the action and response @sean