Inbound email Attachment Size Issues

[JohnnySnow]

Hi Team,

We have currently set the inbound attachment size to 25 mb (glide.email.inbound.max_total_attachment_size_bytes = 26214400) and I tried testing with sending a file of 23 mb and it doesnt get attached. It throws below error "Maximum attachment size of 26214400 bytes exceeded". I'm not sure how to troubleshoot this further.

I tried to increase the size(of the property) to 50mb and it worked fine, but we don't want to increase the size as I might face the same issue when some one sends 45mb file. 

Is there a way to know the total size of the email that is coming into ServiceNow?

Has anyone faced this issue or does any one know the solution to this issue?

[Isaac Vicentini]

Hi @JohnnySnow!

This issue arises because the total email size (including attachments, headers, encoding, and body text) can exceed the set attachment size limit. Even if the attachment alone is within the limit, the email size with encoding may push it over.

You should set the property with a safety margin. Due to encoding (like Base64), attachment sizes can increase by about 30-40%, causing emails to exceed the limit even if attachments appear within it.

To prevent issues, consider increasing the property slightly above the desired limit. For example, if you want to allow attachments up to 25 MB, set the property to around 32-35 MB. This higher limit provides a buffer for the encoding overhead, ensuring that emails with attachments up to 25 MB (before encoding) will still be processed successfully within the adjusted limit.

---

If my answer helped you in any way, please mark it as Helpful / Accept as Solution 🎯

Regards,

Isaac Vicentini.

[JohnnySnow]

Hi Isaac, Yes you are right, I was able to figure out using below KB articles

https://support.servicenow.com/kb?id=kb_article_view&sysparm_article=KB0785037

https://support.servicenow.com/kb?id=kb_article_view&sysparm_article=KB0521772

so as per the above article since I wanted to allow 25mb files (overall size) I set the inbound property to 35 mb i.e. 25Mb x 1.4 (bcoz of encoding) = 35Mb.

[Isaac Vicentini]

That's it @JohnnySnow! Please accept my answer as a solution to be useful to others 🙂

[AkulaN]

Hi 

Could you please clarify this for me?

From what I understand, the maximum size for an inbound email that ServiceNow can process is 25 MB (after encoding). Therefore, the effective limit before encoding is approximately 18 MB, which includes the body, headers, and attachments.

If I were to increase the attachment size to 25 MB or 30 MB, how would the body and headers be handled, given that the total limit is only 18 MB?