Indeed, as others have said above, you can ignore the message or trade data (more correctly referred to as "Encoded" materials) as you would trade other materials in order to even out your stock. The latter is the better option as collecting materials (be them raw or manufactured, or encoded), is never a bad thing, and being maxed out (see below) for any particular thing is blocking one avenue for that gathering process.
In the discussion below, please forgive me for starting by stating some very basic things that you may well know.
Materials are useful for both buying engineering modifications from engineers and for synthesis - as such it's always worth taking any opportunity for gathering and managing your stocks of the materials so that you have what you need when you require it.
There are three main types of Materials - Raw (Sulphur, Iron, etc.) , Manufactured (Shield emitters etc.), or Encoded (various types of data).
In order for you to manage your stock of particular materials, and to cover situations where you might not have a particular material when you need it, you can trade materials at "Material Traders" for other materials, but the exchange rates are poor, so you have to trade wisely as dictated by your current need. As stated above Material traders are found in the contacts menu and each specialise in just one of the three types of material (Raw" Manufactured, or Encoded).
Materials have grades "1" being very common (and used in lower grade engineering upgrades) , "5" being extremely rare (and used in the top grade upgrades).
For each of the three main types of material, there are several subtypes (not so easy to apprieciate, but for instance one subtyoe of Manufactured materials is to do with heat management, and another to do with conduction). The subtype distinction is important to understand when trading materials.
The higher grades of materials are extremely valuable to commanders, and deserve wise management.
As I said above, exchange rates are poor. To grade lower grade materials for the next grade within the same sub category takes SIX of the lower grade to obtain just one of the next grade up. Similarly, to grade for the SAME grade of material in another subtype costs is a six to one ratio. Trading DOWN within a subtype obtains THREE of the next lower grade for one of the higher. Trading both cross-subtype, and cross-grade, incurs both multipliers, and so is even worse value)
As higher grade materials are hard to obtain, it's generally poor practice to trade them away. It's better to trade up, or at a push to the same grade across subtypes. If you are linked to Inara (well worth doing), Inara will keep track of your materials and provides a good visualisation of your stock.
You can only store so many of each individual material. You can keep 300 of a grade one such as Iron, 250 of a grade two, up to 100 of a grade five. Materials are only expended when purchasing upgrades or synthesis. They are never lost of your ship or SRV is destroyed. Those quantities (300,250 etc.) seem a lot but condidering that Grade 5 engineering can cost nine of a material to complete, and the poor exchange rates, you can get through them quickly. Materials are NOT cargo, they take no cargo space, have no mass,, and do not require cargo rack space (which can lead to the odd situation where synthesising limpets, which are cargo, makes your ship heavier in an instant!).