Unable to generate thumbnails/Large folders time out

[4m2c4bl3]

I'm using php 7.2 with v1.2.2
The thumbnail folders are not being generated. I get no error, the _thumbnail folder does not appear.

When I try and open a large gallery of 195 images, I get the error 'nanogallery2: Could not retrieve nanoPhotosProvider2 data. Error: error - Maximum execution time of 30 seconds exceeded'. I saw on the site that you said to refresh a lot of times after the initial install to get rid of the time out errors, but they haven't gone away, and since no thumbnails are being generated, I assume this behavior won't stop.

My smaller gallery of 7 photos is able to show the 'temporary' blurred preview thumbnails, however the larger gallery does not.

If it helps, here are my permissions. The subfolders inside _content all have the same permission as it.

[Kris-B]

depending of the performances of your server, you may have to refresh your page several times to generate all the thumbnails (including the blurred preview)