Hi @Manny,
This issue is very similar to one discussed here.
That is, given:
you have just over a half-a-million reads across 296 alignment positions. That is a lot of reads! Are you sure you are using the correct sequence file? Typically this command is ran with ASVs / OTUs as input.
If you run qiime phylogeny align-to-tree-mafft-fasttree --help , you'll find that there is a potentially useful flag: --p-partree. Try running with this flag and let us know if it works.