I am new and getting strings

Hello. I am very new to 3D printing. About one week in. I purchased a flashforge dreamer and it seems pretty straightforward except I am having one issue. Sometimes when I do a printing it will print the base and about 1/4 inch up and then all of a sudden the filament is just a bunch of strings. It does not do it on all of my prints. I have been downloading STL files from thingiverse and I was wondering if you guys believe this could be a problem in the download or if there is something else I should be looking at. I appreciate any feedback and I look forward to being a part of this forum.

we need information.
print settings: temps, speed etc
material being used

and yes some thingiverse models will have errors.

flashprint will usually fix most.

select the model, click 'edit' and select 'fix model'.

If that doesn't work, check that the model is actually slicing properly.

sometimes parts of models are designed with areas that are thinner than a standard extrusion width. - approx 0.45mm - and those parts of the model can get ignored during the slice.

I appreciate your response. I will check that and get more information. I'm still learning but I'm trying. I appreciate the feedback