Yes, at this point the show was technically cancelled. There’s a historic photo (seen below) of the entire cast flicking off the camera which depicted their honest feelings about the situation.

Thankfully, after an unfortunate hiatus, they were picked up by TNT and given a fifth season and a handful of tv movies (that are sprinkled throughout the continuity) TNT threw their whole guts into B5 and gave them tons of support. Unfortunately season 5 was still the lowest in terms of viewership, and their attempts at spinoff series and more movies ultimately fizzled out.