If your channel is suspended, the status widget in the top left corner will display the reason assigned by Joystream verification team.
Here is the list of suspended reasons that are currently defined
CopyrightBreach - when YT channel reposts videos from other channels or creators.
MisleadingContent - when creators are promoting content of questionable integrity, like deposit/ pyramid schemes and ml marketing. Or simply when thumbnails, channel description etc do not match with the playback content.
UnsupportedTopic - Gore, violence, porn, all the categories that are in severe violation of terms of service
ProgramTermsExploit - purchased subscribers, comments and views by bots, or channels created with the aim to exploit the rewards program. For example channel has no videos or only 1 video uploaded recently.
Decision about channel suspended is non-negotiable and cannot be revisited. Sync videos for suspended channels are not supported, however such channels can still benefit from the referrals scheme, which is open for all.