There exists a limit of 20 subscriptions per user per app at any given time. When this limit is exceeded, then the following error will be returned.

{
"errorCode":"SUB-505"
"message":"Subscriptions limit exceeded"
"errors":[{
"errorCode":"SUB-505"
"message":"Subscriptions limit exceeded"
}]
}

Do not dismay, there are a few remedies to this that are relatively simple to implement.

**Delete unused subscriptions**

This is relatively obvious I suppose, but the simplest thing to do is delete any and all unused subscriptions, which during active development of an application can inadvertantly accummulate without one knowing.

RingCentral does not yet expose a tool or user interface for developers to use for this purpose, so you will need to call the API to [generate a list of subscriptions][1], and then again to [delete/cancel unwanted subscriptions][2].

**Combine or coalesce subscriptions**

A often under-utilized feature of RingCentral's Subscription API is the ability to subscribe to multiple events via the same subscription. This is achieved by passing in multiple [event filters][3] in your [create subscription request][4].

This is much more economical and will allow you to reclaim some of your subscription capacity.

**Be mindful of subscription expirations**

It is tempting to set an expiration date for a webhook subscription so far in the future it effectively never expires. If you do this too often, it increases the chance of exceeding your subscription limit for any given user. Using expiration dates more mindfully, especially during development, will allow older subscriptions to expire and be reaped by the system more naturally.

[1]: https://developers.ringcentral.com/api-reference/Subscriptions/listSubscriptions
[2]: https://developers.ringcentral.com/api-reference/Subscriptions/deleteSubscription
[3]: https://developers.ringcentral.com/guide/notifications/event-filters
[4]: https://developers.ringcentral.com/api-reference/Subscriptions/createSubscription