AS2 partner returns HTTP 500 and no MDN

You send a file to a trading partner through an AS2 destination, and the partner's server answers HTTP 500 with no receipt (MDN). DocEvent retries, then moves the file to Stuck files.

What you see

On the channel's Routing log tab, open the file (Show failed lists the files that need attention). The AS2 destination's lane shows:

Failed to send message via plugin-send-as2-v1: partner answered HTTP 500

with Response code 500 and the AS2 message ID in its details. DocEvent makes up to 3 attempts, about once a minute. After the last one the destination shows a red stuck tag and the lane offers Reprocess this file.

RFC 4130 asks a receiving AS2 system to report problems such as decryption-failed inside a receipt, with a success HTTP status. A bare 500 means the partner's software did not, so the real reason is in their logs. DocEvent records the first 500 characters of the partner's reply with each refused attempt but does not show it in the console, because a partner's error page can name their internal systems. Ask support for it.

Check first: a website certificate instead of an AS2 certificate

With encryption on (the default), DocEvent encrypts each message to the certificate saved for the partner. The mistake to rule out first is saving the partner's website certificate - the one a browser shows from the padlock on their AS2 URL - instead of their AS2 certificate. A website certificate is a valid certificate, so nothing refuses it, but the partner's AS2 software cannot decrypt a message encrypted to it unless they deliberately reuse that key.

Open Channels → AS2 Partners. In the Trading partners table, a suspect certificate has an orange Website certificate? tag in the Certificate expiry column; hover it for the reasons. DocEvent flags a certificate that names a website and is either issued for web servers (serverAuth key usage) or issued by a certificate authority for 398 days or less. The same warning appears under the certificate box as you paste. It is advisory, so a partner that really does reuse one certificate can still be saved.

To fix it:

1. Ask the partner's EDI or AS2 team for their AS2 certificate - the one their AS2 software decrypts and signs with.
2. Edit the partner and paste it into Partner certificate (PEM). If they encrypt with a different certificate, paste that into Separate encryption certificate (optional). Save, and check the orange tag is gone.
3. Click the red stuck tag on the destination, choose Review, select the file and choose Reprocess selected (or use Reprocess this file on the lane). DocEvent resends it under the same AS2 message ID.

Reprocess within 24 hours of DocEvent receiving the file - after that the source file is deleted and must be sent into the channel again. If the reprocessed file gets the same HTTP 500, contact support with the AS2 message ID before retrying.

Test connection does not catch this: it only checks that DocEvent can connect to the partner's URL and complete TLS, and sends no AS2 message.

Other causes

• The AS2 IDs do not match. DocEvent sends your identity's AS2 ID as AS2-From and the partner's AS2 ID as AS2-To. RFC 4130 makes these case-sensitive and does not require a receipt when the receiver does not recognise them. Compare both, character for character, with the partner's configuration - copy them from the AS2 ID column on AS2 Partners.
• The partner cannot verify your signature. With signing on (the default), the partner checks your signature with your public certificate, installed on their side when the partnership is set up. If they never got it, or you have since changed it, verification fails. Under My AS2 identities, use View public certificate and send it to them.

What to send the partner

• The AS2 message ID - it starts with docevent-, and every attempt and reprocess of the file uses the same one
• The time of each attempt, with your time zone (listed on the lane)
• Your AS2 ID, the AS2 ID you send to, and the URL you send to
• The partner's reply, if support has sent it to you
• The address DocEvent connects from, from Channel static IP addresses

Ask them for the error their AS2 software logged for that message ID.

Related guides

• AS2 filenames - incoming and outgoing
• Channel static IP addresses
• AS2 channels - product overview