Latest fixes and solutions for mongodb errors on FixDevs.https://fixdevs.com/enWed, 25 Mar 2026 00:00:00 GMThttps://fixdevs.com/blog/mongodb-aggregation-not-working/https://fixdevs.com/blog/mongodb-aggregation-not-working/How to fix MongoDB aggregation pipeline issues — $lookup field matching, $unwind on missing fields, $match placement, $group _id, type mismatches, and pipeline debugging.Wed, 25 Mar 2026 00:00:00 GMTmongodbdatabasebackenddebuggingFixDevshttps://fixdevs.com/blog/mongodb-schema-validation-error/https://fixdevs.com/blog/mongodb-schema-validation-error/How to fix MongoDB schema validation errors — $jsonSchema rules, required fields, type mismatches, enum constraints, bypassing validation for migrations, and Mongoose schema conflicts.Sun, 22 Mar 2026 00:00:00 GMTmongodbdatabasenodejsbackenddebuggingFixDevshttps://fixdevs.com/blog/mongodb-replica-set-not-primary/https://fixdevs.com/blog/mongodb-replica-set-not-primary/How to fix MongoDB 'not primary' errors when writing to a replica set — read preference misconfiguration, connecting to a secondary, replica set elections, and write concern settings.Wed, 18 Mar 2026 00:00:00 GMTmongodbdatabasedebuggingbackendFixDevshttps://fixdevs.com/blog/mongoose-validation-failed/https://fixdevs.com/blog/mongoose-validation-failed/How to fix Mongoose ValidationError when saving documents — required field errors, type cast failures, custom validator errors, and how to handle validation in Express APIs properly.Tue, 17 Mar 2026 00:00:00 GMTmongoosemongodbnodejsdebuggingFixDevshttps://fixdevs.com/blog/mongodb-duplicate-key-error/https://fixdevs.com/blog/mongodb-duplicate-key-error/How to fix the MongoDB E11000 duplicate key error by identifying duplicate fields, fixing index conflicts, using upserts, handling null values, and resolving race conditions.Tue, 10 Mar 2026 00:00:00 GMTmongodbdatabasedebuggingFixDevshttps://fixdevs.com/blog/mongodb-connect-econnrefused/https://fixdevs.com/blog/mongodb-connect-econnrefused/How to fix MongoDB 'MongoServerError: bad auth Authentication failed', 'MongoNetworkError: connect ECONNREFUSED 127.0.0.1:27017', and 'MongooseServerSelectionError' connection errors. Covers MongoDB not running, connection string format, Atlas network access, Docker networking, authentication, DNS/SRV issues, TLS/SSL, and Mongoose options.Fri, 02 Jan 2026 00:00:00 GMTmongodbmongoosedatabasedockernodejsFixDevs