Recently I noticed a small problem related to the annotations adding feature on my youtube channel videos, I realized that I can no longer added linked annotations on my youtube uploaded videos or I can’t link annotation to subscribe my channel, and it seemed to be a bug which should get sorted soon, but till then you can follow my fix below to fix this issue.
After some searching I found out there is a simple fix to solve this issue, you just need to the follow the steps below to fix and add a annotation on the video linked to subscribe, associated website etc. For this first login to your youtube channel and locate the video and then go to annotation feature.
Once you have loaded the page which has annotation feature, you will see the option for the Link which allows you to set a link annotation for subscribe and other linked annotations.
But once I click link box and then select subscribe from the other dropdown, everything just reset rather than giving me the option to type in the channel username.
Now the fix to this issue is, you need to copy the URL as mentioned below with your youtube channel name and then copy the same to the text box and it will automatically change to subscribe link.
as you can see in the image below.
This is how you can fix this and add further other types of linked annotations on the youtube video.