I have been using a Drobo 5D3 for years and have had no issues until now. I had it filled with five WD Red NAS drives (6TBx3 and 4TBx2). I wanted to upgrade the size of on of the 4tb drives so took out one and replaced with 6tb WD Red then all lights turned solid red and drobo says “Warning multiple drive have been removed. Please reinsert removed drives” I only removed one drive. I tried replacing the drive i took out but it still says the same thing. My computer does see that the drobo is attached and drives are present. health status of individual drives say Good.
OS: Mac catalina 10.15.7
Drobo firmware: 4.1.4