What happened?

Description

We recently upgraded from Craft 4 to Craft 5 and we noticed that the GraphQL Autocomplete and Explorer stopped working as if the introspection queries stopped working. This error is in the browser console: "Error: Invalid or incomplete introspection result. Ensure that you are passing "data" property of introspection response and no "errors" was returned alongside: undefined."

This happens with all of our environments - local with DDEV and staging.

Steps to reproduce

1. Login to the Control Panel
2. Navigate to GraphQL > GraphiQL
3. Click Explorer
4. See "No Schema Available"

Expected behavior

The explorer shows the GraphQL schema and pressing CTRL + Space suggests GraphQL symbols.

Actual behavior

No schema or autocomplete available.

Craft CMS version

Craft Pro 5.5.3

PHP version

8.2.26

Operating system and version

Linux 5.15.0-1058-aws

Database type and version

MySQL 8.0.40

Image driver and version

Imagick 3.7.0 (ImageMagick 6.9.10-23)

Installed plugins and versions

• Amazon S3 | 2.2.1
• Amazon SES | 3.1.0
• Blitz | 5.9.6
• FeedMe | 6.5.0
• Freeform | 5.7.3
• Guest Entries | 4.0.1
• ImageOptimize | 5.0.3
• Neo | 5.2.17
• oEmbed | 3.1.1
• Redactor | 4.2.0
• Redactor Custom Styles | 5.0.0
• Retcon | 3.2.1
• Retour | 5.0.3
• Reverse Relations | 3.0.0
• SEOmatic | 5.1.7
• Sprig | 3.5.1