By looking at their telegram channel, you're not the only one experiencing this kind of issue, tronwatch seems to be giving bad mnenonic seed phrases or private keys that isn't compatible with the present tronlink wallet. I also found that tronwatch has stopped operating since 2018, so the odds of recovering your coins is pretty slim.
I found other people's recommendation but I think it's too technical which can be overwhelming to follow
[1][1]
TronWatch desktop wallet restore