The fiscal sponsor must be a 501(c)(3) organization as recognized by the IRS. The fiscal sponsor cannot be an organization whose tax-exempt status is pending. The sponsored project must be able to qualify for exemption under section 501(c)(3), even if the project has no intention of ever applying for it.
Pressing the Ignore button on the listed invitation on the LinkedIn site is effectively a soft rejection. The message then moves to your Archived folder. You can later choose to open the message again and accept the request.
Mention the suspect on instagram, of course you can mention people who have blocked you and can also ask why and sort the bits off. 1  If you are concerned so much about the security of your account then go Private Mode.  If you are blocked, the person who has blocked you can still see your profile. Block them.