Self-service accounts (under the Pro plan) can be upgraded and downgraded by users via the account’s settings page without assistance from the Cloudinary team.
Possible reasons why the account is not eligible for a downgrade:
Exceeding plan limits of lower plan
Example: downgrading to the Free plan which has a 25 credit limit. If the current credit usage of your account is above 25 credits, then our system will not permit the downgrade to occur.
Note that Cloudinary quotas are calculated by examining current storage usage and the last 30 days of transformations and bandwidth usage. This is also why current usage goes up and down over time and doesn't 'reset' on a calendar month or on the billing cycle month.
More information about how quotas are calculated can be found in the following support article: https://support.cloudinary.com/hc/en-us/articles/203125631-How-does-Cloudinary-count-my-plan-s-quotas-and-what-does-every-quota-mean-
Exceeding user limits of lower plan
All plans offer at least 3 user seats starting from the Free plan. However, on Advanced plans and higher, plans include 5 user seats.
To downgrade to a lower plan, you must delete enough users until your user count is within the lower plan's limits.
If needed, extra user seats may be purchased through your account's "Users" settings section.
Exceeding product environment limits of lower plan
By default, our Free plan allows for one product environment, while our Plus plan allows for two, and our Advanced plan allows for three.
To downgrade to a lower plan, you must delete enough product environments until your product environment count is within the lower plan's limits.
If needed, extra product environment slots may be purchased through your account's main settings view.
Account has configurations that aren't supported/aren't free for lower plans
Some settings and configurations on your account will require the help of our Support Team before downgrading is possible. One example is having a CNAME set up on your account, which is available for accounts with an Advanced plan or higher.
If the account has a balance due from failed payments or unpaid overages, downgrades to lower plans are not available.
For any further questions or assistance with downgrading your account, please submit a support ticket so that our Support Team can assist you: https://support.cloudinary.com/hc/en-us/requests/new