Mail messages will receive but not send on all devices

I'm not sure what's going on here. Suddenly, for no apparent reason, I can no longer send email through Mail out of ANY of any of my three Macs, iphone and ipad. I can receive mail but not send.

Checked with Bluehost and they say everything is fine on their end. They say it's Mail.

After I send a message I get "Unable to verify account name or password." Yet, it's the same password used to receive mail and I DO RECEIVE mail.

Tried retyping the password into the outgoing settings, still no go.

Around this time I've been getting a lot of iCloud can't connect too. I don't use it nor want it but wondering if it's somehow related.

Problem is on iphone, ipad, two MacBook Pros, and a tower. Using OS10.12.6 on primary Laptop. Iphone OS 10.3.3. iPad 11.0.3...

Just don't understand how they are all effected the same way when nothing's been touched. I'm independent producer running a small business and this is killing me. Thanks.