Pi-hole version is v4.3.5-458-g2de5362 (Latest: v4.4)
AdminLTE version is v4.3.2-462-g8e51f754 (Latest: v4.3.3)
FTL version is vDev-d395b3b (Latest: v4.3.1)
When adding https://raw.githubusercontent.com/anudeepND/blacklist/master/adservers.txt for example to the adlist via web gui, it pops up following error:
Error, something went wrong! While executing: UNIQUE constraint failed: adlist.address
If I take off the https:// from the string it imports the list correctly.
This means the list has already been added, note that you can (and should obviously) import each list only once.
From your debug log, I see that the list https://raw.githubusercontent.com/anudeepND/blacklist/master/adservers.txt was added already on 2020-01-25 19:08:07 with the comment: Migrated from /etc/pihole/adlists.list.
Oh I didn't even think about that. English is not my native language, I didn't understand the error means the entry already exists, but in retrospect I see now how it says exactly that.
I don't think it should be necessary for the whole process to stop if only 1 domain gives an error message.
For example: trying to add many lists with one erroneous (or duplicate) entry somewhere at the top results in an error and all the domains after the erroneous one are not added.
Is that the desired behaviour? In my opinion it would be easier / better if all the other domains that are valid would still be added.