“INVALID_FIELD_FOR_INSERT_UPDATE: Task: bad field names on insert/update call”
If you see an error message in full that reads “[“create”,”INVALID_FIELD_FOR_INSERT_UPDATE: Task: bad field names on insert/update call: MME__EmailFromAddress__c, MME__EmailDirection__c, MME__EmailDate__c, MME__EmailFromName_c, MME__Type__c”]” and you are seeing Reprocess in the Email Cloud, it is because you are using Group edition of Salesforce.com and uploading emails as tasks into Activity History. This edition of Salesforce.com has limitations on custom fields.
To correct the problem, you need to add the new custom fields Email Date, Email Direction, Email From Name, Email From Address, and MME Type on Page Layout for Task Activity.
In Salesforce go to Setup
In Classic, on the left sidebar under App Setup/Build, expand Customize, expand Activities and click on Task Page Layout. Click on fields mentioned (and indicated in red in screenshot below) and drag onto page layout. They can be placed in section Other Information. After adding all five fields, click SAVE at top.
In Lightning, on left sidebar under Platform Tools, Expand Objects and Fields, Expand Object Manager. In list, scroll to find TASK and click that label. OR in Quick find at top of left sidebar, type in TASK and click where it appears below.
To the left, click Page Layouts. For Task Layout click drop down to right and choose Edit.
The steps will then be the same as described above for Classic. Find the five fields at top and drag down onto page layout. Click SAVE at top.