"Spotify can't play this (...) you can import it" for albums I have imported already

[AJIX]

Plan

Free

Country

United Kingdom (Scotland)

Device

Desktop PC

Operating System

Windows 10

My Question or Issue

This issue is of a similar nature to the one that's already seemingly going around in this thread, however, the solutions offered there haven't helped at all.

I purchased an album (Daemonheim - Widerwelt) recently, downloaded it and noticed that all the songs were greyed out on the Spotify listing for the album. Usually, in these cases, importing the songs into the local files as MP3s let them become playable - however, I noticed that this wasn't the case here and the songs remain grey/unplayable. Not only this, but some (strangely, not all, just some - I can list them if you require) of the other albums that I had done this with in the past have also became unplayable, despite them having been previously playable. I've checked the tags of the MP3 files to make sure they match up with how it's tagged on Spotify, and they do (barring differences in capitalization, which in my past experiences, hasn't mattered anyway), as shown in the attached picture. Additionally, I've made certain that the folder it is in is definitely being imported - it shows up in my local files, but it is still unable to be played on the album's page.

Any help with this issue would be very much appreciated. Thanks in advance.