ios mail and calendar always need to re login (I already enable Dot ask again for 90 days)

1) ios mail and calendar always need to re login (I already enable Dot ask again for

90 days)

some time will pop "Enter the passowrd for hte exchange account" muti time in a day

2)  ios default calendar auto switch from my M365 to icloud and person M365 Calendar

missing but  Delegate Calendar is can show after I renew my apple care+ in my phone .