Hi Mirko,
This is April, I'll be happy to assist you. Sorry to hear that you're having issue receiving emails. Let me help you out.
Based on the information you rarely receive emails, and you already checked your blacklist settings, but nothing is listed.
May I know if those emails that you have issue receiving are from Gmail? Microsoft are aware of the issue and this is under investigation. You may check on this link for reference: https://support.microsoft.com/de-de/office/fixes-or-workarounds-for-recent-issues-on-outlook-com-8c95d913-d96b-4065-9171-e1fa44b03ff5
Review your Email filters or Rules:
Open your Emails settings and look for any filters, rules or mail flow settings. Make sure there aren't any rules that might be automatically deleting, moving or archiving your incoming messages without your knowledge.
Try accessing your email through the website interface:
- Sign in directly through your email provider website. Sometimes mails apps don't sync all folders properly or might over-look server-side filters and rules.
Check email quota:
- Some email providers may silently block incoming messages when storage is full. Try deleting unimportant emails and make sure to empty your trash or deleted items to free up.
If the issue continues, please don’t hesitate to contact us again. We’re here to help, and we appreciate your continued trust in us.
Warm Regards,
April P.
Independent Advisor