Tom Francis wrote:
I'm using an older laptop now that has Thunderbird installed. When I
powered up the program this morning, Thunderbird updated to the most
recent version and now, when I try to send an email, it's telling me I
have a "invalid certificate" or "same certificate" and rejects the
email from being sent.

I've spent the last hour trying to figure it out, but I can't find any
information on this. I never needed it before, now I do. It's the
same server I've used for years. The other odd thing is that my main
computer upgraded T-bird fine with no problems.

Any hints?

I'm using the portable because I'm officially crippled - seriously.
Short term, but crippled. :)

I'd appreciate any thoughts on it.

You might look around and see what is in your certificate settings.
Look in Tools, Options, Advanced, Certificates.
There is an option there to 'View Certificates'.
That might at least help you get a hint about where the problem is.

Chris