If the support wizard isn't able to solve your problem, please send an email to firstname.lastname@example.org for assistance. Support cannot be offered in this topic, and you will just be directed to the email.
In floatplane.com, click the cog in the bottom left, next to your name, then click "settings". In the tab nav that appears, click "Connected Accounts", then click the refresh icon next to Linus Tech Tips. (The steps are mostly similar to https://linustechtips.com/main/topic/976027-how-to-link-discord-to-your-floatplanecom-account/). If that doesn't work, or it would be easier, you can also log out, then log back in using the LTT forum, as this will also force a resync.
If you can't access videos on floatplane.com, follow these instructions to resync your accounts.