If the bed fails to heat up, the most likely cause is a hardware fault in the electrical system. The fist step should be ruling out any software issues, since they are trivial and can be quickly fixed. First try restarting the printer and restarting MatterControl on the touch interface.
Then, to check if there was any effect, try and preheat the quick change build platform. If an error is displayed, make note if it for the support staff. If not, wait to see if the bed temperature increases, which should occur in less than a minute.
If no error is displayed, and the bed fails to heat up, it is appropriate to begin troubleshooting hardware. Begin by shutting off the printer and unplugging it from the wall. Many Infinity 3D Printers have an external fuse box on the back of the machine, as shown in the picture below.
I you find similar fuses on the back of the printer, check the fuses. To check the fuses remove them and inspect them visually, a blown fuse should have a noticeable break in the internal connections. If you are unsure, use the resistance or continuity setting of a multi-meter to check the fuses. Also check the security of the fuses and the fuse housing, if there is any sign of damage, contact a support representative.
If the printer does not have a fuse box in this location, the fuses are located directly on the PMB, and are likely not the cause of the bed heating issue. Proceed to the next troubleshooting step.
Another possible location where the connection to the PMB might fail is the 2-pin connector in the back left corner of the interior of the printer, shown in the picture below (#1).
First, cut the cable tie (#2), being careful not to damage the ribbon cable or the red cable sheathing. Then disconnect the 2-pin connector (#1). Inside the connector on the bed end (the side with red wires) there are female pins as shown in the following picture.
Then, to improve the connection between these female pins and the male pins in the other connector, pinch the metal connectors using either tweezers or a small flat head screwdriver. The connectors should only need minor deformation to improve contact.
Reconnect the the cables and use a new cable tie to anchor the 2-pin connector. Pug in the printer and turn it back on to check if the problem has been resolved. If the problem persists, contact the support team to continue targeted troubleshooting.