550 Too many invalid recipients error code

[Tom_Kerlin2]

Hello,

In one of our distribution lists we had about 70 domains with "550 Too many invalid recipients" listed as the cause for the email becoming invalid. I browsed to find additional info. on this error code, but also wanted confirmation, since the explanation that's provided is pretty circular.

As I understand it, this type of error code appears when sending to a distribution list that has a high number of invalid recipients per email domain?

FYI - In a recent send, my work email hard bounced and had the same error code, and my sales ops team thinks that this error code is taking place for active clients and making them invalid when they shouldn't be. Has anybody experienced something similar? I'm thinking about running a batch campaign to change these domains back to Email Invalid: False but wasn't sure if this was the best approach.

Thanks for your help,

Tom

[Grégoire_Miche2 · Accepted solution]

Hi Tom,

AFAIK, it can be too many recipients per email provider (e.g. gmail), so if many of your customers were using gmail apps services, that could also cause the issue.

The very bad about this one is that it will flag as invalid email addresses that are not, just because some other addresses has been invalid in the same batch.

The good news is that it is easy to catch it in the triggered campaign and unflag them immediately.

You can also process them with a daily batch.

-Greg

[SanfordWhiteman]

Not just too many in the same batch but potentially too many across different batches from different Marketo instances using the same sender IP.

[Tom_Kerlin2]

Thanks Sanford. Are you referring to clients using a shared sender IP and not a dedicated IP?

[Grégoire_Miche2]

Hi Tom,

It can happen with both.

Of course, the risk with a shared IP is that you are suffering from someone else's bad data. With a dedicated one, it's only the result of you own dirty database

-Greg