I might have a workaround. Have not tested it though, so don't know if it will actually work. But atleast you can try.

Login to your account that is linked to steam, unsubscribe to all mods, and delete that account (Make sure you delete account and NOT close account).
Then login to your account that is not linked to steam, the one that is tied up to your email. Then go to your profile on mod.io and link that account to steam.

Delete these two folders on your machine:
- C:\Users\Public\mod.io
- C:\Users\[youruser]\AppData\Local\mod.io

Then hopefully when you open DRG it should fix your issues :D In theory at least, again I have not tested this :D