> [!WARNING]
> [Zyte API](../../zyte-api/get-started.md#zyte-api) is replacing Smart Proxy Manager. It is
> no longer possible to sign up to Smart Proxy Manager. If you are an
> existing Smart Proxy Manager user, see spm-migrate.

# How to fix concurrency issues?

Smart Proxy Manager standard plans (Stater, Basic, Advanced) are limited by
concurrency. This means the code you use to retrieve web pages through Smart
Proxy Manaager cannot execute more than a certain number of requests in
parallel.

If you exceed this concurrency limit, you will start receiving errors with code
429. For more details on this error and other Smart Proxy Manager errors see zyte-proxy-errors.

To fix these concurrency errors you need to reduce the number of requests you
run in parallel from the code you use to access Smart Proxy Manager. How this
is done depends on the language and business logic of your scraping code.

Alternatively, you can upgrade to a larger plan with more concurrency or to an
Enterprise plan which doesn’t have concurrency limits.