API Error Codes

Error CodeSub CodeReasonSolution
TM_3201GE_102Mandatory Field "subject" was set as Empty Value.Set the Mandatory Fields as proper values instead of setting Empty in the API.
Mandatory Field "from" is missing.Add the mandatory "from" field.
No recipient field found.Add either "to", "cc" or "bcc" fields.
Mandatory field "Mail Template Key" is missing.Add the mandatory "Mail Template Key" field.
TM_3301SM_101Invalid JSON.

Kindly check your API syntax.

TM_3501UE_106Invalid File Cache Key. 

Obtain proper File Cache Key from the respective Mail Agent in your File Cache tab. 

MTR_101Invalid Template Key. 

Obtain proper Template Key from the respective Mail Agent.

TM_3601SERR_156Email sending IP is not in the allowed IPs list.You need to add the relevant IP to the allowed IPs list from the settings. Learn more


Sender address domain is not verified in your Mail Agent.

Use the sender address domain that is verified in your Mail Agent.


Mandatory Field "from" has Invalid Value.

Set the Mandatory Fields as proper values in the API.

Note: target_value in the error response shows the field where an invalid email address is set.​
Same error response if an Invalid Values is set in any of these fields: cc, bcc, mime-type in attachments, reply_to, File Cache Key

Mandatory Field "to" has Invalid Value.
Mandatory Field "bounce_address" is missing or has Invalid Value.
SM_128Your ZeptoMail account is yet to be reviewed and approved by us.Get your account reviewed and then send your emails using API.
SERR_157Sendmail token is invalid. Obtain proper Sendmail token from the configuration settings within your Mail Agent.
TM_8001SM_127Total number of attachments exceeding the limit.Allowed total number of attachments < = 60.
Fields exceeding limits.

Total number of addresses exceeding the limit. The allowed number of unique values for each of these fields are:

i) reply_to < = 40

ii) to < = 340

iii) cc < = 100

iv) bcc < = 100

SM_129Character limit exceeded for the name field for any of these parameters - from, to, reply_to, cc, bcc.Allowed character limit < = 250.
Subject field exceeding the character count limit.Allowed subject line character count < = 500.
Attachment size exceeding the limit.​Allowed attachment size < = 15 MB.​​
Exceeding the character limit in attachment filename.​Allowed Attachment FileName Characters Length <=150.​​


Before you get started it is important to know that ZeptoMail is for sending transactional emails like welcome emailers, password resets emails, OTPs. We do not support sending of bulk emails or promotional emails like newsletters or marketing campaign emails. If you are looking for a bulk email provider, you can visit Zoho Campaigns.