Outlook showing emails 'sent' but not received by recipients

Hello,

For the last couple of weeks, occasionally but not always, the emails I send are not reaching the recipients. This is a serious problem. They appear in the Sent folder, but they are not even reaching the recipient's junk folder. I was about to send my CV to someone, and it's the first time I'm sending an email to a personal address, especially one with a Hotmail extension. I sent the email three times within a 5-minute interval, but it stubbornly didn't reach the recipient. I'm not on any blacklist, and there are no filters; still, it's not reaching. Later, I sent the same email from my inactive Gmail account to the same address, and it reached instantly.

Last week, I received an email from a company for a job interview and responded promptly. Today, they sent the same email as an SMS. I asked if they received my response eight days ago, and unbelievably, they didn't. This email delivery issue, especially in crucial matters, is genuinely frustrating. The company has been waiting for my response for eight days. Unbelievable!

Even the emails I send to my spouse sometimes reach and sometimes don't.

Please, don't provide the usual responses like "if it's in the Sent folder in Outlook, the problem is related to the recipient's account." There is a problem here, and if it's not resolved, I will consider working with another personal email provider.