As a part of the security updates, Authorize.net has made a change to the delimiters in the response transaction. This change impacts many Magento 1 online stores, as the base Magento code was unable to properly process. This change went live on Tuesday, January 22, 2019.
See more information on this topic on Authorize.net at: https://community.developer.authorize.net/t5/News-and-Announcements/Changes-to-Supported-Characters-Jan-22-2019/td-p/65435
Invalid Character Inputs
|Char Representation||ASCII Value(s)|
|Non-printable characters||0 – 31|
Here is the fix for the issue, which involves altering the Magento code to accommodate the changed delimiter. Specifically:
This fix requires developer advise first to avoid any mess up on the system.
If you are on a lookout for a helping hand/seeking guidance for regarding this matter, consult Bliss Web Solution Pvt. Ltd. at the earliest.