MinghuiYu
We noticed this issue as well when users are managing distribution lists in Exchange Online. I believe this is a known issue, ID: https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fnam.safelink.emails.azure.net%2Fredirect%2F%3Fdestination%3Dhttps%253A%252F%252Fadmin.microsoft.com%252FAdminPortal%252Fhome%2523%252Fservicehealth%252F%253A%252Falerts%252FEX679489%253Fshdlinksource%253DIncidentMail%26p%3DbT01YWI0ZWU2Yi1jYjI2LTQzNmYtOGJhNS1lNDZhOTU2NGZkMGImdT1hZW8mbD1ob21l&data=05%7C01%7Cbrian.b.ko%40healthpartners.com%7C5d786a4a3fc1401fc75008dbc68957e7%7C9539230a521345429ca6b0ec58c41a4d%7C0%7C0%7C638322065420235920%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=7ALHKYAsqO4aEVNEvUYnZ0eCeQ7SIG8AZOeSIczS684%3D&reserved=0
I hope it gets fixed soon.