Hi @drhorg
please follow the advise from @chleverenz. It could be any reason. But to make it simple try the following
1. Log in to https://make.powerapps.com/
2. Sign in with your credentials
3. Choose the environment from the top right corner. Adding screenshot for reference

4. If you don't see the environment which means you don't have access yet. Ask your system administrator to add you to the appropriate role.
Additional:
1. In the same screenshot. Click settings icon > Check plans. Make sure you have a license assigned. like below

Hope it helps.
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