A lot of people are having problems retrieving the exif automatically from images that are hosted on flickr. Even if you have included the exif on flickr, once you have embedded it at POTN, it is missing and AMASS cannot retrieve it. This is caused by the fact that flickr includes the exif only when you embed the "original" file, the original file being the size you uploaded to flickr. This means that if you upload an image of 2400px on the long side to flickr and you then want to post that picture here, you cannot use the original size and will need to choose another, say, Large or Medium, or any size that would be allowed on POTN. However, that means you are not embedding the original file and thus flickr strips the exif and AMASS cannot retrieve it automatically.
Also, and this is important!, make sure you choose the "Original" size and not simply the right size from the BBCode list at flickr. For images of 1280px on the long side (POTN's allowed max size now) this is not a problem as it will only be listed once as the Original size (provided you uploaded it as a 1280px image). However, a lot of people will want to add older images to their galleries that are 1024px on the long side. If you uploaded these images to flickr as 1024px with the exif included and posted them here, at POTN, but AMASS cannot retrieve the meta data, you need to check what size you embedded here because flickr's "Large" size happens to also be 1024px on the long side and so chances are you picked that size and not the Original size. Here is what I mean:
This is an older image of mine that I uploaded to flickr as 1024px on the long side. Clicking on the BBCode gives me this:
However, if you click open the list, you will see this:
One other thing to realise is that flickr will protect your "original" images, no matter how you set your preferences in flickr's settings. This means that if you use the Fetch tool it will work, but it will download flickr's "Large" size at best and not the "Original" size and that means that using the Fetch tool with flickr, AMASS will not be able to retrieve meta data. I have tested every possible way that I could think of, played with flickr's settings and in the end the only way that I was able to retrieve meta data automatically from flickr is to manually grab the BBCode for the "Original" size and paste it here at POTN.
Hope this helps.
EDIT: Sometimes AMASS cannot retrieve the lens. This will often happen when an extender was used. My own experience is that with some cameras (like my old 40D with a Kenko 1.4x) AMASS retrieves the lens without any problems. With other cameras (like my 1DIIn with a Kenko 1.4x) AMASS cannot retrieve the lens.
EDIT: The FETCH tool now works with flickr! For this you simply go to the photo page of the photo you want to embed, copy the URL and paste it in FETCH. It will embed only the 1024px size (which flickr calls "Large"), but it will retrieve the exif now. Which is a very nice improvement indeed! If you want your images to be 1280px wide, you still need to copy/paste the BBCode yourself, like I explained above.
EDIT: Apparently most of the above is no longer relevant as other formats than the "original" will also show the exif now. That is, if you have included it in the image of course.
EDIT 21-01-2018: I saw reports that exif for downsized images from flickr are not including exif, so I'm checking.
I am embedding an image that I uploaded to flickr as 1600px (so that is the "original" size). I grabbed the BBCode for the 1024px downsized version on flickr and pasted it here.
That's a successful test as the exif is indeed visible above the pic, even though it's not actually included in the image. AMASS works wonders sometimes. [IMAGE'S LINK: https://flic.kr/p/23qhmsD]Robin / Roodborst (Erithacus rubecula) by Levina de Ruijter, on Flickr