Q: Twilio SMS message Not Delivered with unknown error We're having this weird problem with Twilio SMS messages hanging with status.
We have tried sending from different Twilio phone numbers to make sure it isn't a problem with that particular number being blocked and none of them go through.
Our system uses SMS messages in the standard form of two-step authentication with a code and a short message to the user inside the SMS body.
The carrier that the message sent is failing is Tune Talk (A Malaysian one).
The error in the Twilio Logs/Console I see is:
Status: Undelivered
Error: (Error: 30008) Unknown error. None 

Message SID if it's in any way useful is: SM1024a2d519cf4f6bbfcbc838587cb2af
Any insight on why this is happening would be greatly welcomed.

A: We had also the same issue with phones that used to receive messages.
The problem is carrier blocking/filtering.
Every carrier uses different filters.
Some carriers block messages with 90% the same content, others use rate filtering (1 message per second or more) others use a combination. The blocking is not forever thought.
Twilio gives the following possible solutions: 
Check that the phone you were sending to is turned on and can receive SMS


*

*Ensure that the phone is not roaming off network. We cannot
guarantee message delivery on roaming phones.

*Try sending to other phones who have the same mobile carrier.
If messages to other phones go through, the issue is likely device
related. Try rebooting the device or contact the mobile carrier for
help.    

*If you are sending SMS from an alphanumeric sender ID, see if using
a Twilio phone number works better. We've observed that certain
networks may block alpha sender IDs.    

*Try sending a shorter message to the phone, with simple content that
does not include any special characters. This would give our support
team an idea as to whether the failure is related to concatenation
or character encoding. 

*Twilio support can help investigate what went
wrong with our carriers. Please open a support request and include a
minimum of 3 or more message SIDs where a 30008 error was thrown.
Per our carriers' requirements, these SIDs can be no older than 48
hours at most.


Check -> Error 30008
Another solution is to use a 5digit code phone number.

A: Boris, error 30008 is certainly less descriptive than one would hope. In this case, it would be best to send that Message Sid along to support where we can dig a little deeper into the specifics. 
Though it doesn't sound like it in this case, if there were a problem with your code, you could check out a production ready account verification tutorial here.  

A: Came here because of exactly the same problem.  I have someone who successfully received SMSes just 12 days ago, using the same Australian number, getting a 30008 for every attempt to send to them today.  That's a really average-quality error message right there.
The user states that they ported the number from Telstra to Vodafone, but that was 3 months ago.  I'm guessing that the forwarding is broken:
http://www.commsalliance.com.au/__data/assets/pdf_file/0013/2326/G565_2009.pdf
In particular:
1.4.4 Where internationally originated SMS is supported donor routing
must be supported wherever bilateral agreement exists for the
national leg, as international networks are not likely to access an
Australian mobile number portability database prior to routing the
message. However, certain limitations apply – see Appendix A.
Since Twilio aren't sending from an Australian number, they probably aren't looking through the number portability database.  This would be my suspect cause for any failure to SMS route to a country with number portability.

A: I've had some of these errors when doing MMS's.
If I look at the detail in the Twilio console, there is additional detail and a secondary error message "12300 Invalid Content-Type. Attempt to retrieve MediaUrl returned an unsupported Content-Type."
I was putting images up on S3, but not setting the Content-Type of the image when I put it on S3.

A: In my case, the problem was that I was including a website URL in the message.
Once I removed it (replaced it with a simple name) it worked.
I'm not sure whether the issue was the URL itself (e.g. the network considers it spam) or the fact that it contained characters like /.
