Error: Invalid user address

[Mr_X1]

I have recevied a issue where user has mentioned the below issue.
He is getting such email.

Can you please suggest what to do here, what steps should i take ?

received from: XXXX@service-now.com
sent direct: XXXX@service-now.com
sent copied:

Error: Invalid user address

Error message below:
550 - Requested action not taken: no such user here

Message details:
Subject:
Sent date: Sat May 23 22:43:57 UTC 2020
MAIL FROM: XXXX@service-now.com
RCPT TO: 424-399-9999@vtext.com
From:
XXXX Global Service Desk <XXXX@service-now.com>

To:
424-399-9999@vtext.com

Size: 2.2 KiB

[Mr_X1]

Hello Michael, Thank you for this information, I found it.

Can you please tell me, What happens if i delete this entry. " Its a type :: SMS "

& what changes are required to make it work properly

[Michael Ritchie · Accepted solution]

You will need to consult Verizon or the user to understand if that phone number is still correct.  ServiceNow is basically using email to SMS gateways meaning some providers like Verizon offer an email address to send a text message.  Now this is very old technology and some carriers, especially outside the US, are scaling that back.  I do recall reading on the community that Verizon was considering charging for this and no longer free.

If you delete this notification device, that error will not longer appear because ServiceNow will no longer send out notifications to this device.

Please mark this post or any as helpful or the correct answer to your question if applicable so others viewing may benefit.

[Mr_X1]

Thank You Michael..