Hello sir,
If run this commandline "qiime tools import --type 'SampleData[SequencesWithQuality]' --input-path se-33-manifest --output-path single-end-demux.qza --input-format SingleEndFastqManifestPhred33V2" means, I was getting error like your se-33-manifest is not in proper format. But I ran this same commandline without V2 letter means, I am not getting error.
What does that last letter v2 represent? To me, se-33-manifest was in proper format. If you find any mistake, please let me know sir.
Thanking you in advance for your help.