Monoprice Mini MPIII - Bed adherence issues. HELP Please

[sliderule01]

I have a Monoprice mini MPIIIV2 which I have used successfully for the past several months. Yesterday I ran into a problem that I can not figure out how to fix. Right now, I can not get the extruded filament to adhere to the build plate. I have leveled the build plate, used a glue stick and blue tape. Nothing is working. I am printing in PLA with an extruder temperature of 200 and plate temperature of 60. These settings worked very well in the past for about 1.5 kg of PLA. This happened suddenly.

A little background:

Yesterday, my nozzle became clogged. I removed the nozzle and the small heat exchanger (the round thing with fins). I also unscrewed the throat to gain access to the inside of the heat exchanger. It turned out that the heat changer was clogged, and I was able to remove the clog from the heat exchanger. I put everything back together and things fired up as always. I did a test extrude of filament and it extruded fine. I tried to print something, and all I got was spaghetti around the nozzle - absolutely no adherence. I leveled the build plate; cleaned it off with alcohol. Tried to print - no adherence. Used tape - no luck. Used glue stick - again no luck. I am wondering if I changed the nozzle height when I put the hot end back together. Any suggestions?

Scott