Carnegie Mellon University


Send calendar invitations to a Google Group instead of a Mailman list to ensure that recipients see the event on their calendars.

Google Calendar cannot view the individual recipients on a Mailman list, so recipients will not see the event on their calendar unless they accept the invitation.

However, Google Calendar can view recipients in a Google Group, so recipients will see the event on their calendars even if they do not explicitly accept the invitation.

Group managers can request a Google Group if they don’t have one already.

As long as both mailman lists are included in the same email message, the person should only receive one email.

As a Mailman list administrator, you can obtain a list of all subscribed addresses and names. 

  1. Click Administer My Lists and click the list you want.
  2. Click Passwords.
  3. Enter a new list password (NOT your Andrew password).
  4. Send mail to <listname>, with the word  help in the Subject line and who <list password>  in the body.
  5. Once you receive your list email, create a new list password (steps 1&2).


Note: Addresses for subscribers with the "hide" option will not be returned. You can only view these via the Membership Management page.

Mailman has a 40k message body limit. To change the limit:

  1. Go to
  2. Click Administer My Lists and log in with your Andrew userID and password.
  3. Click the name of the list you want to change.
  4. Click General Options> Maximum length in kilobytes (KB) of a message body.
  5. Set the value to 0 (zero) to remove limitations.
  6. Click Submit Your Changes.

If you administer more than 50 mailman lists, you may receive the following error: 

Bad Request
Your browser sent a request that this server could not understand.
Size of a request header field exceeds server limit.
A cookie is generated for each list that you administer and most browsers can handle no more than 50 cookies for a single site. 
To temporarily get to the list you need:
  1. Follow your browser's Help to clear the cache and cookies.
  2. Navigate directly to the administration page for your list -

Since this will continue to be an issue, we suggest creating a document with the direct URL for all your mailing lists.

  1. Go to and click Administer My Lists.
  2. Select the contents of that page and copy it.
  3. Paste the contents into a Word document and save it somewhere you can access it conveniently
  4. Follow your browser's Help to clear the cache and cookies.
  5. To administer your list, open the document and click the list name
  6. Repeat these steps when you add new lists you administer.

By default, Mailman lists require that the list address (or an alias defined in the list configuration) appear in the To or CC field; if it does not, the message is held for moderation with this message.

To configure your list to allow messages that do not contain the list address (or a defined alias) in the To or CC field:

  1. Go to
  2. Click Administer My Lists and log in with your Andrew userID and password.
  3. Click the name of the list you want to change.
  4. Click Privacy options > Recipient Filters.
  5. Set the "Must posts have list named in destination (to, cc) field or be among the acceptable alias names, specified below" option to no.
  6. Click Submit Your Changes.

Message not being sent to person in CC

Mailman removes an address from the To or CC line if that address is also subscribed to the Mailman list. This prevents subscribers from receiving multiple copies of the message or receiving multiple copies of replies to the message.

This error has nothing to do with the number of people subscribed to the list. Mailman lists can contain thousands of members. It occurs because the total number of addresses in the To: and Cc: headers of the post equals or exceeds recipient limit settings in Privacy Options.

To avoid this hold message, you can do one of the following:

  • Reduce the amount of people the initial email is sent to (in the To: or CC: fields).
  • Send the email to only the list itself.
  • Increase the maximum setting of recipients. The default Mailman recipient limit is 10. Go to Privacy Options > Recipient Filters and increase the max_num_recipients.

IMPORTANT: Please be mindful of changing the default recipient limit setting. Most people on your list will not want to see a large number of visible addresses in a mailing list post.

An unmoderated mailman list may generate a Moderator Approval hold for several reasons:

  • Too many recipients 
  • Implicit destination error
  • Message body is too big

Please refer to the solutions in Moderation and Sender Filters for assistance.