Why do I get a "too many addresses" error when I add addresses to my Approved and Blocked Senders lists?
Symptom: An attempt to add addresses to a sender list gets an error message, and the addresses are not added.
Common Causes: There is a maximum of 4,000 characters for each list (organization approved senders, organization blocked senders, user approved senders, user blocked senders). If each address or domain is roughly 30 to 40 characters, each approved/blocked sender list can include approximately 100 to 130 addresses and domains. For each address configured, add an additional 2 characters to get an accurate size count.
Solution: To free up more space, delete addresses that are no longer used. You may consider adding an address from a user’s list to the appropriate organization-level list to improve filtering for all users while freeing up space for that particular user.
More Information: For more information, see Size Limits of Senders Lists in the Administration Guidee.