Thanks so much for posting in a new thread.
I noticed that your work email actually has your personal Gmail email address as a connected inbox. Was that intentional? In any case, connecting a different email address from your user email will not allow you to send emails from that different email address.
However, you mentioned that you used to be able to send emails from HubSpot, despite not having had a connected inbox beforehand. After doing some digging, here is what I've been able to find on this front.
All portals created since 7/11/16 are required to connect their inbox to send from the CRM. Your portal was created in November. You may have been able to do so before, but now are no longer able to; this is because this rule was not fully enforced until recently. Here is why this requirement exists.
When you send emails form the CRM with a connected inbox, all of the emails that you send go through your actual email client, and appear in your "sent" box thereafter. They are sent with your email client's sending domains, and are fully associated with your email address, ensuring optimal deliverability.
When you send emails from the CRM without a connected inbox, your emails are send through HubSpot's IP addresses and sending domains. Everything comes from our servers, but your email address shows as the sender. This often causes significant confusion and concern for recipients' inboxes: some email clients see the discrepancy between the sending email address and sending IP address, and mark the email as unsafe, or potential spam. This means that emails sent through the CRM without a connected inbox can have very poor deliverability.
For this reason, we chose to phase out this functionality, as it often caused more issues than anything else. Now, we recommend that users only send emails from the CRM when they have a connected inbox.
Let me know if all of this makes sense, and whether I can clarify anything else regarding this issue!
All the best,