Troubleshooting View-Only Configuration role assignment
When configuring the connection to a source on-premises Exchange server, the connection wizard checks if the provided admin account is assigned the View-Only Configuration role. If the role is missing, the Configuration step fails (Fig. 1.), as the program is not able to check whether all the necessary management roles are assigned to this account, and you get the following error:
Failed to check if role 'View-Only Configuration' is assigned to admin account
To continue with the configuration, you will be asked to provide the credentials of another account that has the View-Only Configuration role assigned (Fig. 2.). If you're not sure which users are assigned this role, you can check that manually, following this KB article. By default, an admin user who belongs to the Organization Management role group should have this role assigned. Keep in mind that this account will not be used to connect to the source Exchange server.
When you provide the correct credentials, the program will check if the admin account used for the migration is missing any other roles required for the migration process. If so, the program will attempt to assign them automatically (Fig. 3.). Click Yes to proceed.
If the program is unable to assign the missing roles, it means that the account provided in the Configuration step doesn't have appropriate rights to do so. To assign these roles, you will be asked to enter credentials of an admin user who is a member of the Organization Management role group. Please also check, if you didn't misspell the entered credentials.
Provide a valid UPN and password and click OK. The missing roles will be assigned, and the Configuration step will finish successfully.
Note that only the credentials specified in the Admin account step are used to connect to the source Exchange server. Credentials provided in the Configuration step are only used once to assign the missing roles. Therefore, you will not be asked to provide the credentials of other admin users again as long as you use the same admin account for the migration process.
If you don't want the program to assign any roles automatically, you can do it manually, following the steps described in this KB article.