Email to members@ not working -- spam??

Recently we have been having trouble sending email to our members.
Two mailings to members-4547@toastmastersclubs.org have resulted in the following error response

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toastmastersclubs.org  rejected your message to the following email addresses:This email address is being protected from spambots. You need JavaScript enabled to view it.
Your message couldn't be delivered because it's suspected of being spam. For best practices when sending email, refer to the guidelines found here: [url] go.microsoft.com/fwlink/?LinkID=526654 [/url].
  toastmastersclubs.org  gave this error:
Decision Engine classified the mail item was rejected because of IP Block (from outbound normal IP pools) -> 550 5.7.1 <This email address is being protected from spambots. You need JavaScript enabled to view it.>... Mail from 40.107.236.41 refused because IP is on SpamCop - see [url] spamcop.net/bl.shtml [/url]

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I'm not sure what this is all about. IP address 40.107.236.41 is apparently connected to a Microsoft Azure server in Virginia. We're in California.

A few days ago, SpamCop showed 40.107.236.41 as listed in its block list. Today it doesn't, and mailings to members@ seem to be working again.

We've been using FTH for years with no spam problems, and don't know why this would start (and stop) all of a sudden.

Is this our problem somehow?

You need to talk to your email host as they are the ones that are labeled as spammers. There is nothing we can do about the issue.

"Mail from 40.107.236.41 refused because IP is on SpamCop - see  spamcop.net/bl.shtml"