Hi, I'm Sudipto. Welcome to JustAnswer. I'm reviewing your question now, and will post back with your reply ASAP
As you have seen an error message related to Waste ink absorber already, so that means the error code also indicates towards that. Now, the job of the waste ink absorber or purge unit is to collect the dripping ink from the cartridges after a print job, so that the ink do not damage any spare of the printer. The best solution for this problem is replacing the waste ink absorber pads from any repair shop, but before that you can try the steps below to reset the error code, if it works then, you can use the printer for few more days, but ultimately you have to change the pads.
Please check out this Youtube video, it shows the steps to clear the 5B00 error code: https://youtu.be/0waX_GF-h7U
I do hope it helps.
Just following up. Were you able to view the video and get the printer reset? Is it working now?