# RTC - Connection ERROR : There is a communication protocol..

**URL:** <https://www.dynamicsuser.net/t/rtc-connection-error-there-is-a-communication-protocol/23259>\
**Category:** Technical Forum\
**Created:** [October 22, 2009, 8:07am UTC](https://www.dynamicsuser.net/t/rtc-connection-error-there-is-a-communication-protocol/23259 "2009-10-22T08:07:34Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![subrata.bauri](https://avatars.discourse-cdn.com/v4/letter/s/f04885/32.png) [@subrata.bauri](https://www.dynamicsuser.net/u/subrata.bauri)\
**Post date:** [October 22, 2009, 8:07am UTC](https://www.dynamicsuser.net/t/rtc-connection-error-there-is-a-communication-protocol/23259/1 "2009-10-22T08:07:34Z")

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Hi all,

I have faced a problem when trying to connect the Db thru RTC.It gives the error message “There is a communication protocol mismatch between the client and the server”. But Other Client Pc can connect the Db thru RTC easily.

I have found that Server RTC Version is 6.0.27808.0  
and client(s) RTC Version is 6.0.29626.0.

Then why One can connect and another Pc can not ?? [+o(]

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**Author:** ![munib](https://avatars.discourse-cdn.com/v4/letter/m/91b2a8/32.png) [@munib](https://www.dynamicsuser.net/u/munib)\
**Post date:** [October 30, 2009, 11:23am UTC](https://www.dynamicsuser.net/t/rtc-connection-error-there-is-a-communication-protocol/23259/2 "2009-10-30T11:23:37Z")

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Looks like you have installed NAV2009 (no SP1) as the server and you are using NAV2009SP1 client to open it.

Make sure both are the same.

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**Author:** ![AlexWiley](https://avatars.discourse-cdn.com/v4/letter/a/6de8d8/32.png) [@AlexWiley](https://www.dynamicsuser.net/u/AlexWiley)\
**Post date:** [December 30, 2009, 11:05pm UTC](https://www.dynamicsuser.net/t/rtc-connection-error-there-is-a-communication-protocol/23259/3 "2009-12-30T23:05:14Z")

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I have this exact same error except both versions are 6.0.27808.0

Suggestions?

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**Author:** ![munib](https://avatars.discourse-cdn.com/v4/letter/m/91b2a8/32.png) [@munib](https://www.dynamicsuser.net/u/munib)\
**Post date:** [January 7, 2010, 2:26pm UTC](https://www.dynamicsuser.net/t/rtc-connection-error-there-is-a-communication-protocol/23259/4 "2010-01-07T14:26:45Z")

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Alex,

The only suggestion I can make is - make sure they are the same.

Lastly, reinstall.

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**Author:** ![Peter\_Wibeck\_MSFT](https://avatars.discourse-cdn.com/v4/letter/p/ee7513/32.png) [@Peter\_Wibeck\_MSFT](https://www.dynamicsuser.net/u/Peter_Wibeck_MSFT)\
**Post date:** [January 13, 2010, 10:50am UTC](https://www.dynamicsuser.net/t/rtc-connection-error-there-is-a-communication-protocol/23259/5 "2010-01-13T10:50:54Z")

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Pls verify that the server version is the same as the RTC client you are using to connect to it. You are talking about server RTC version with may differ from the acctual server installed on the system.

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**Author:** ![aashish1206](https://avatars.discourse-cdn.com/v4/letter/a/ecccb3/32.png) [@aashish1206](https://www.dynamicsuser.net/u/aashish1206)\
**Post date:** [November 1, 2010, 8:00am UTC](https://www.dynamicsuser.net/t/rtc-connection-error-there-is-a-communication-protocol/23259/6 "2010-11-01T08:00:47Z")

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Hi All, even i faced the same issue.The following steps resolved my issue.

1. Make sure IIS is installed on server,since the RTC works if SQL reporting services and IIS is installed.
2. Uninstall the RTC and Classic on clients machine.Then install NAV 2009 SP1.Use **Setup** option from the Disk or if the installation dump is stored on server.
3. Then use **Install Demo** option,this will install RTC,Classic Client and SQL.

Regards,

Ashish Kokney