Contrary to Trump paranoia, 99.999% of mailed-in ballots are received and duly and accurately processed.

Can't help your state mine is marked 4 WWW.HOWIEHAWKINS.US ready to hand deliver to my county election office

You can check in PA right away, though they sent me an email saying it was received. Not sure how your state works.

Every state should have a voter registration website where all voting info should be available. I know my state of New Mexico does. It has instructions on how to track your ballot.

I hope your state has a system as nice as mine does in Oklahoma. Their website told me when it was mailed to me, when it was received and finally when it was counted.

Most States have websites for that.
Or contact your county board of elections to find out how one can check on whether your vote got received.

No idea..sorry

Each state has different rules. Follow this link to see the rules.
[commoncause.org]

There is a note for Connecticut voters inside that article. Good luck.