At Metaforms each organization has its own sub-domain hosted under metaforms.org. You should use https://[organization name].metaforms.org to reach your instance. For example if you work at Strawberry corp. the URL should be https://strawberry.metaforms.org. Also please check the e-mails you got from us while setting up your account, the URL is shown there as well. If you still can't find it, please contact us.