The OTU table contains unknown OTUs!

Hello RStudio Community !!!

I'm trying to do a phylogram using Unifrac distance followed command line:

unifracs <- GUniFrac(otu_file, rooted_tree, alpha = c(0.0,0.5,1.0))$unifracs

But it's not working and I have the following error message:

Error in GUniFrac(otu_file, rooted_tree, alpha = c(0, 0.5, 1)) :
The OTU table contains unknown OTUs! OTU names in the OTU table and the tree should match!

I checked the OTU table and also the tree file and they have the same information. Does anyone know this error and could help me?

Thanks so much,
Jessy